Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120 Halle, Germany Martin-Luther-University Halle-Wittenberg, Institute of Organic Chemistry, Kurt-Mothes-Str. 2, 06120 Halle, Germany Tel: +49 345 5582 1301; Fax: +49 345 5582 1309 This article is part of the Thematic Series "Multicomponent reactions". <chunk>Synthesis of (−)-julocrotine and a diversity oriented Ugi-approach to analogues and probes</chunk> diversity oriented synthesis julocrotine leishmania Mitsunobu reaction Ugi reaction An improved total synthesis of (−)-julocrotine in three steps from Cbz-glutamine, in 51% overall yield, is presented. To demonstrate the potential of the heterocyclic moiety for diversity oriented synthesis, a series of (−)-julocrotine analogues was synthesized by employing the heterocyclic precursor as an amino input in Ugi four-component reactions (Ugi-4CR) .
<chunk>Introduction</chunk> Julocrotine ( 1 ) is a natural glutarimide alkaloid isolated from several plants of the genus Croton , including Croton cuneatus Klotzsch, which is used by Amazonia natives in anti-inflammatory and analgesic medicines. The structure of this glutarimide-containing alkaloid was first proposed in 1960, based upon a series of degradative experiments, but only confirmed in 2008 by X-ray analysis . Most interestingly, it was found to inhibit the growth of promastigote and amastigote forms of the protozoan Leishmania amazonensis (L.) with no cytotoxicity against the host cell . This parasite causes cutaneous leishmaniasis, a neglected disease that affects more than 12 million people in tropical countries . In addition, the glutarimide motif can be considered as a privileged structure. Compounds with this pharmacophore often exhibit a wide range of biological properties including anti-inflammatory , antitumor , and anticonvulsive properties . Because of the low yields of julocrotine obtained through isolation from natural sources and the necessity to gain access to larger quantities of this substance for further biological screening, Silva and Joussef developed a straightforward total synthesis in six steps . Starting from L-glutamic acid, their chiral-pool approach yielded the desired optically active natural product in 41% overall yield. After analyzing the structure of (−)-julocrotine, we set out to synthesize it in only three steps from commercially available L-Cbz-glutamine, in a sequence of cyclization (a), N-alkylation (b), and the removal of the protecting group followed by acylation with ( S )-2-methylbutanoic acid (c) ( ). Based on this flexible route, we also envisioned the synthesis of derivatives utilizing post-cyclization transformations by multicomponent reactions. This diversity-driven approach benefits from the fact that the heterocyclic moiety may be considered a privileged structural element for bioactivity.
<chunk>Results and Discussion</chunk> The synthetic approach, illustrated in , starts from Cbz-glutamine 2 , which reacted in the presence of dicyclohexylcarbodiimide (DCC) and N -hydroxysuccinimide (NHS) in DMF to afford Cbz-glutarimide 3 in 76% yield in optically pure form . To alkylate the imide-moiety, glutarimide 3 was reacted with phenylethyl bromide in the presence of potassium carbonate at room temperature. The desired compound 4 was obtained in 98% isolated yield, but analysis revealed racemization. Indeed, the equilibration at the chiral center of 4 can be observed even in the presence of weak bases such as potassium carbonate . Thus, we decided to use a base-free N-alkylation protocol, namely the Mitsunobu reaction of 3 and the readily available 2-phenylethanol . This protocol gave the desired optically active product in 90% yield ([α] 20 D −29.2). The key intermediate 4 was hydrogenated on Pd/C at room temperature to afford 5 , which was coupled with ( S )-2-methylbutanoic acid in the presence of EDCl and HOBt to afford (−)-julocrotine ( 1 ) in 73% yield, over two steps. The HRMS, 1 H and 13 C NMR spectra, optical rotation, and melting point of 1 were consistent with the reported data . For the diversity oriented synthesis the advanced intermediate 5 was used as the amino component in an Ugi-4CR with ( S )-2-methylbutanoic acid, hydrophobic amino acids, formaldehyde and tert -butyl isocyanide ( ). These analogues possess a protease-resistant peptoid scaffold and this might lead to an enhanced activity . In this endeavor, all Ugi reactions were initiated by pre-imine formation of 5 and reaction with formaldehyde as the oxo-component, after which the multicomponent reaction was completed by the addition of ( S )-2-methylbutanoic acid, Boc-Gly, Boc-Ala, Boc-Val, Boc-Leu, Boc-Phe and Boc-Ile and tert -butyl isocyanide. Following this procedure, the desired optically active compounds 6a–g were obtained in 55–63% yields. Their structures were confirmed by 1 H, 13 C NMR and HRMS spectra. Finally, the Ugi-4CR was utilized for the synthesis of a molecular probe prototype of 1 , which can be used for intercalation studies ( ). For this propose, the natural product scaffold should be attached through a spacer to a reporter tag, which is normally a luminescent group or a dye. The advanced intermediate 5 was converted to the respective imine as depicted in and then reacted with ( S )-2-methylbutanoic acid and isonitrile 7 to afford the intermediate 8 in 61% yield. This compound was then hydrogenated to afford 9 and then directly coupled with 1-pyrenemethylamine, by using EDCl as coupling reagent, to yield the designed probe prototype 10 in 80% yield (from 8 ). Pyrene derivative 10 exhibited strong blue luminescence in both solution and solid phase. This probe may be used for tracking the (−)-julocrotine in biological systems, in particular in promastigote and amastigote forms of protozoan Leishmania amazonensis (L.) . It could be helpful to elucidate the to-date unknown mode of action of this natural product in the parasite.
<chunk>Conclusion</chunk> In summary, a highly efficient method to synthesize (−)-julocrotine ( 1 ) in three steps from Cbz-glutamine 2 was developed. The approach affords the natural product in 51% overall yield. The versatility of the developed protocol was demonstrated in the synthesis of seven julocrotine analogues and a molecular probe utilizing Ugi-4CRs. The desired compounds 6a–g and 10 were obtained in good yields.
Retrosynthetic scheme for (−)-julocrotine ( 1 ).
Reactions and conditions: (a) DCC, NHS, DMF 80 °C, 18 h, 76%. (b) Ph(CH 2 ) 2 Br, K 2 CO 3 , acetone, r.t., 20 h, (±) -4 , 98%. (b') Ph(CH 2 ) 2 OH, DIAD, PPh 3 , THF, r.t., 20 h, (−)- 4 , 90%. (c) H 2 , 10% w/w Pd/C, MeOH, r.t., 4 h, quant. (d) ( S )-2-methylbutanoic acid, EDCl, HOBt, CH 2 Cl 2 , r.t., 16 h, 73%. Reactions and conditions: (a) (CH 2 O) n , MeOH, r.t., 2 h then, RCOOH and t -BuNC, r.t., 18 h. Reactions and conditions: (a) (CH 2 O) n , MeOH, r.t., 2 h then, ( S )-2-methylbutanoic acid and 7 , r.t. 18 h, 61%. (b) H 2 , 10% w/w Pd/C, MeOH, r.t., 10 h. (c) 1-pyrenemethylamine hydrochloride, Et 3 N, EDCl, DMAP, CH 2 Cl 2 , r.t., 24 h, 80% over two steps. ASALPLLZVFIFMF-ZFWWWQNUSA-N InChI=1S/C18H24N2O3/c1-3-13(2)17(22)19-15-9-10-16(21)20(18(15)23)12-11-14-7-5-4-6-8-14/h4-8,13,15H,3,9-12H2,1-2H3,(H,19,22)/t13-,15-/m0/s1 CC[C@H](C)C(=O)N[C@H]1CCC(=O)N(CCC2=CC=CC=C2)C1=O C1=CC=CC(=C1)CCN2C(CC[C@@H](C2=O)NC([C@H](CC)C)=O)=O |(140.37,-86.25,;134.62,-76.29,;123.12,-76.29,;117.37,-86.25,;123.12,-96.21,;134.62,-96.21,;117.39,-106.14,;105.93,-106.14,;100.2,-116.06,;105.94,-126.02,;100.19,-135.98,;88.69,-135.97,;82.94,-126.01,;88.7,-116.03,;82.97,-106.11,;71.48,-126.01,;65.75,-116.09,;54.29,-116.09,;48.56,-106.16,;37.1,-106.16,;48.56,-126.01,;71.48,-106.16,;117.4,-126.02,)| AuxInfo=1/1/N:22,23,18,2,1,3,6,4,11,12,7,8,19,5,10,13,20,9,17,14,16,21,15/E:(5,6)(7,8)/it:im/rA:23nCCCCCCCCCC.eCCCNOONCC.oCOCC/rB:d1;s2;d3;s4;s1d5;s5;s7;;s9;s10;s11;s12;s8s9s13;d9;d13;N10;;s18;s17s19;d20;s18;P19;/rC:140,3677,-86,2526,0;134,6177,-76,2933,0;123,1177,-76,2933,0;117,3677,-86,2526,0;123,1177,-96,2119,0;134,6177,-96,2119,0;117,3877,-106,1366,0;105,9276,-106,1366,0;88,6976,-116,0330,0;82,9426,-126,0122,0;88,6877,-135,9743,0;100,1877,-135,9799,0;105,9427,-126,0235,0;100,1976,-116,0613,0;82,9675,-106,1083,0;117,4027,-126,0235,0;71,4825,-126,0122,0;48,5624,-106,1627,0;54,2924,-116,0874,0;65,7525,-116,0874,0;71,4825,-106,1627,0;37,1023,-106,1627,0;48,5624,-126,0122,0; C18H24N2O3 CDK 04302613362D 0 0 0 0 0 999 V3000 M V30 BEGIN CTAB M V30 COUNTS 23 24 0 0 1 M V30 BEGIN ATOM M V30 1 C 140.36774 -86.25256 0 0 M V30 2 C 134.61774 -76.29327 0 0 M V30 3 C 123.11772 -76.29327 0 0 M V30 4 C 117.36771 -86.25256 0 0 M V30 5 C 123.11772 -96.21188 0 0 M V30 6 C 134.61774 -96.21188 0 0 M V30 7 C 117.38768 -106.13661 0 0 M V30 8 C 105.9276 -106.13661 0 0 M V30 9 C 88.69756 -116.03297 0 0 M V30 10 C 82.94263 -126.01216 0 0 CFG=1 M V30 11 C 88.68771 -135.97429 0 0 M V30 12 C 100.18774 -135.97995 0 0 M V30 13 C 105.94266 -126.02348 0 0 M V30 14 N 100.19756 -116.06134 0 0 M V30 15 O 82.9675 -106.10826 0 0 M V30 16 O 117.40274 -126.02348 0 0 M V30 17 N 71.48253 -126.01216 0 0 M V30 18 C 48.56236 -106.1627 0 0 M V30 19 C 54.29239 -116.08745 0 0 CFG=2 M V30 20 C 65.75247 -116.08745 0 0 M V30 21 O 71.48253 -106.1627 0 0 M V30 22 C 37.10226 -106.1627 0 0 M V30 23 C 48.56236 -126.01216 0 0 M V30 END ATOM M V30 BEGIN BOND M V30 1 2 1 2 M V30 2 1 2 3 M V30 3 2 3 4 M V30 4 1 4 5 M V30 5 2 5 6 M V30 6 1 6 1 M V30 7 1 5 7 M V30 8 1 7 8 M V30 9 1 9 10 M V30 10 1 10 11 M V30 11 1 11 12 M V30 12 1 12 13 M V30 13 1 13 14 M V30 14 1 14 9 M V30 15 2 9 15 M V30 16 2 13 16 M V30 17 1 14 8 M V30 18 1 18 19 M V30 19 1 19 20 M V30 20 2 20 21 M V30 21 1 18 22 M V30 22 1 17 20 M V30 23 1 19 23 CFG=1 M V30 24 1 10 17 CFG=3 M V30 END BOND M V30 END CTAB M END ARFWPJVFZFYKJK-NSHDSACASA-N InChI=1S/C13H16N2O2/c14-11-6-7-12(16)15(13(11)17)9-8-10-4-2-1-3-5-10/h1-5,11H,6-9,14H2/t11-/m0/s1 C1=CC=C(C=C1)CCN2C(=O)CC[C@@H](C2=O)N C1([C@H](CCC(N1CCC2=CC=CC=C2)=O)N)=O |(163.51,-149.69,;152.02,-149.68,;146.26,-159.64,;152.01,-169.6,;163.51,-169.61,;169.26,-159.65,;180.72,-159.65,;186.45,-149.73,;197.91,-149.73,;203.66,-159.69,;215.16,-159.69,;220.91,-149.73,;215.16,-139.77,;203.66,-139.77,;169.24,-179.53,;146.29,-139.76,;169.24,-139.77,)| AuxInfo=1/0/N:15,14,16,13,17,3,4,11,10,12,2,5,1,9,6,8,7/E:(2,3)(4,5)/it:im/rA:17nCC.eCCCNOONCCCCCCCC/rB:s1;s2;s3;s4;s1s5;d1;d5;N2;s6;s10;s11;d12;s13;d14;s15;s12d16;/rC:163,5123,-149,6923,0;152,0172,-149,6839,0;146,2624,-159,6403,0;152,0075,-169,6025,0;163,5075,-169,6081,0;169,2624,-159,6517,0;169,2424,-139,7676,0;169,2375,-179,5328,0;146,2872,-139,7592,0;180,7224,-159,6517,0;186,4525,-149,7269,0;197,9126,-149,7269,0;203,6626,-159,6862,0;215,1625,-159,6862,0;220,9126,-149,7269,0;215,1626,-139,7676,0;203,6626,-139,7676,0; C13H16N2O2 CDK 04302613362D 0 0 0 0 0 999 V3000 M V30 BEGIN CTAB M V30 COUNTS 17 18 0 0 1 M V30 BEGIN ATOM M V30 1 C 163.51234 -149.69234 0 0 M V30 2 C 152.01724 -149.68387 0 0 CFG=1 M V30 3 C 146.26236 -159.64034 0 0 M V30 4 C 152.00748 -169.60246 0 0 M V30 5 C 163.50746 -169.60812 0 0 M V30 6 N 169.26236 -159.65166 0 0 M V30 7 O 169.24239 -139.76762 0 0 M V30 8 O 169.2375 -179.53284 0 0 M V30 9 N 146.28722 -139.75916 0 0 M V30 10 C 180.72244 -159.65166 0 0 M V30 11 C 186.45247 -149.72694 0 0 M V30 12 C 197.91255 -149.72694 0 0 M V30 13 C 203.66255 -159.68623 0 0 M V30 14 C 215.16254 -159.68623 0 0 M V30 15 C 220.91255 -149.72694 0 0 M V30 16 C 215.16255 -139.76764 0 0 M V30 17 C 203.66255 -139.76764 0 0 M V30 END ATOM M V30 BEGIN BOND M V30 1 1 1 2 M V30 2 1 2 3 M V30 3 1 3 4 M V30 4 1 4 5 M V30 5 1 5 6 M V30 6 1 6 1 M V30 7 2 1 7 M V30 8 2 5 8 M V30 9 1 6 10 M V30 10 1 10 11 M V30 11 1 11 12 M V30 12 2 12 13 M V30 13 1 13 14 M V30 14 2 14 15 M V30 15 1 15 16 M V30 16 2 16 17 M V30 17 1 17 12 M V30 18 1 2 9 CFG=3 M V30 END BOND M V30 END CTAB M END JIMLDJNLXLMGLX-JTQLQIEISA-N InChI=1S/C13H16N2O5/c14-11(16)7-6-10(12(17)18)15-13(19)20-8-9-4-2-1-3-5-9/h1-5,10H,6-8H2,(H2,14,16)(H,15,19)(H,17,18)/t10-/m0/s1 C1=CC=C(C=C1)COC(=O)N[C@@H](CCC(=O)N)C(=O)O C([C@H](CCC(=O)N)NC(OCC=1C=CC=CC1)=O)(=O)O |(59.34,-83.76,;49.41,-89.49,;39.49,-83.76,;29.56,-89.49,;19.64,-83.76,;9.71,-89.49,;19.64,-72.26,;49.41,-100.95,;39.45,-106.7,;39.45,-118.16,;49.38,-123.89,;49.38,-135.35,;29.77,-146.67,;29.77,-169.36,;49.4,-180.67,;69,-169.35,;69.02,-146.7,;29.53,-100.97,;59.34,-72.3,;69.3,-89.51,)| AuxInfo=1/1/N:12,11,13,16,14,3,4,17,15,2,5,1,19,9,8,7,6,10,20,18/E:(2,3)(4,5)(17,18)/it:im/rA:20nCC.eCCCOONNOCCCCCCCOCO/rB:s1;s2;s3;s4;d1;d5;P2;s5;s1;;d11;s12;d13;s14;s11d15;s15;s17;s8s18;d19;/rC:59,3366,-83,7620,0;49,4119,-89,4920,0;39,4872,-83,7620,0;29,5625,-89,4920,0;19,6378,-83,7620,0;59,3366,-72,3019,0;9,7130,-89,4920,0;49,4119,-100,9521,0;19,6378,-72,2620,0;69,2959,-89,5120,0;69,0032,-169,3453,0;49,3959,-180,6656,0;29,7719,-169,3566,0;29,7705,-146,6735,0;49,3773,-135,3523,0;69,0212,-146,6960,0;49,3773,-123,8922,0;39,4526,-118,1622,0;39,4526,-106,7021,0;29,5279,-100,9721,0; C13H16N2O5 C1=CC=C(C=C1)COC(=O)* Cbz CDK 04302613362D 0 0 0 0 0 999 V3000 M V30 BEGIN CTAB M V30 COUNTS 20 20 0 0 1 M V30 BEGIN ATOM M V30 1 C 59.33662 -83.76201 0 0 M V30 2 C 49.4119 -89.49203 0 0 CFG=1 M V30 3 C 39.48718 -83.76201 0 0 M V30 4 C 29.56248 -89.49203 0 0 M V30 5 C 19.63776 -83.76201 0 0 M V30 6 O 59.33662 -72.30194 0 0 M V30 7 O 9.71304 -89.49203 0 0 M V30 8 N 49.4119 -100.95212 0 0 M V30 9 N 19.63776 -72.26201 0 0 M V30 10 O 69.29591 -89.51201 0 0 M V30 11 C 69.00323 -169.34532 0 0 M V30 12 C 49.39587 -180.66563 0 0 M V30 13 C 29.77194 -169.35657 0 0 M V30 14 C 29.77046 -146.67346 0 0 M V30 15 C 49.37735 -135.35231 0 0 M V30 16 C 69.02124 -146.69595 0 0 M V30 17 C 49.37735 -123.89223 0 0 M V30 18 O 39.45262 -118.1622 0 0 M V30 19 C 39.45262 -106.70212 0 0 M V30 20 O 29.52789 -100.97209 0 0 M V30 END ATOM M V30 BEGIN BOND M V30 1 1 1 2 M V30 2 1 2 3 M V30 3 1 3 4 M V30 4 1 4 5 M V30 5 2 1 6 M V30 6 2 5 7 M V30 7 1 2 8 CFG=1 M V30 8 1 5 9 M V30 9 1 1 10 M V30 10 2 11 12 M V30 11 1 12 13 M V30 12 2 13 14 M V30 13 1 14 15 M V30 14 2 15 16 M V30 15 1 11 16 M V30 16 1 15 17 M V30 17 1 17 18 M V30 18 1 18 19 M V30 19 2 19 20 M V30 20 1 8 19 M V30 END BOND M V30 END CTAB M END JJFWWAGUYKLJRN-JTQLQIEISA-N InChI=1S/C13H14N2O4/c16-11-7-6-10(12(17)15-11)14-13(18)19-8-9-4-2-1-3-5-9/h1-5,10H,6-8H2,(H,14,18)(H,15,16,17)/t10-/m0/s1 C1=CC=C(C=C1)COC(=O)N[C@H]2CCC(=O)NC2=O C1([C@H](CCC(N1)=O)NC(OCC=2C=CC=CC2)=O)=O |(162.4,-79.54,;150.88,-79.54,;145.12,-89.5,;150.87,-99.46,;162.37,-99.47,;168.12,-89.51,;168.1,-109.39,;145.15,-69.62,;-485.87,-21.89,;-474.42,-22.28,;-468.35,-12.55,;-456.9,-12.95,;-446.26,-32.93,;-423.59,-33.7,;-411.61,-14.48,;-422.26,5.51,;-444.89,6.3,;-491.26,-11.77,;168.13,-69.61,)| AuxInfo=1/1/N:11,10,12,15,13,3,4,16,14,2,5,1,18,9,6,8,7,19,17/E:(2,3)(4,5)/it:im/rA:19nCC.eCCCNOONCCCCCCCOCO/rB:s1;s2;s3;s4;s1s5;d1;d5;N2;;d10;s11;d12;s13;s10d14;s14;s16;s9s17;d18;/rC:162,3984,-79,5371,0;150,8788,-79,5427,0;145,1239,-89,4992,0;150,8690,-99,4613,0;162,3690,-99,4670,0;168,1239,-89,5105,0;168,1285,-69,6124,0;168,0990,-109,3917,0;145,1487,-69,6180,0;-422,2553,5,5054,0;-411,6120,-14,4775,0;-423,5854,-33,7033,0;-446,2553,-32,9292,0;-456,8995,-12,9467,0;-444,8908,6,2979,0;-468,3528,-12,5548,0;-474,4189,-22,2778,0;-485,8723,-21,8860,0;-491,2596,-11,7711,0; C13H14N2O4 C1=CC=C(C=C1)COC(=O)* Cbz CDK 04302613362D 0 0 0 0 0 999 V3000 M V30 BEGIN CTAB M V30 COUNTS 19 20 0 0 1 M V30 BEGIN ATOM M V30 1 C 162.39844 -79.53708 0 0 M V30 2 C 150.87877 -79.54274 0 0 CFG=1 M V30 3 C 145.12386 -89.49919 0 0 M V30 4 C 150.86897 -99.46133 0 0 M V30 5 C 162.36896 -99.46698 0 0 M V30 6 N 168.12386 -89.51053 0 0 M V30 7 O 168.12848 -69.61235 0 0 M V30 8 O 168.099 -109.39171 0 0 M V30 9 N 145.14873 -69.61801 0 0 M V30 10 C -422.25531 5.50543 0 0 M V30 11 C -411.612 -14.47751 0 0 M V30 12 C -423.58545 -33.70328 0 0 M V30 13 C -446.25531 -32.92915 0 0 M V30 14 C -456.89948 -12.94666 0 0 M V30 15 C -444.89081 6.29787 0 0 M V30 16 C -468.35284 -12.55482 0 0 M V30 17 O -474.41888 -22.2778 0 0 M V30 18 C -485.87225 -21.88599 0 0 M V30 19 O -491.25958 -11.77113 0 0 M V30 END ATOM M V30 BEGIN BOND M V30 1 1 1 2 M V30 2 1 2 3 M V30 3 1 3 4 M V30 4 1 4 5 M V30 5 1 5 6 M V30 6 1 6 1 M V30 7 2 1 7 M V30 8 2 5 8 M V30 9 2 10 11 M V30 10 1 11 12 M V30 11 2 12 13 M V30 12 1 13 14 M V30 13 2 14 15 M V30 14 1 10 15 M V30 15 1 14 16 M V30 16 1 16 17 M V30 17 1 17 18 M V30 18 2 18 19 M V30 19 1 9 18 M V30 20 1 2 9 CFG=3 M V30 END BOND M V30 END CTAB M END KLBZBEZKVLKUOH-SFHVURJKSA-N InChI=1S/C21H22N2O4/c24-19-12-11-18(22-21(26)27-15-17-9-5-2-6-10-17)20(25)23(19)14-13-16-7-3-1-4-8-16/h1-10,18H,11-15H2,(H,22,26)/t18-/m0/s1 C1=CC=C(C=C1)CCN2C(=O)CC[C@@H](C2=O)NC(=O)OCC3=CC=CC=C3 C1([C@H](CCC(N1CCC2=CC=CC=C2)=O)NC(OCC=3C=CC=CC3)=O)=O |(42.4,-149.7,;30.9,-149.69,;25.15,-159.64,;30.89,-169.61,;42.39,-169.61,;48.15,-159.66,;59.61,-159.66,;65.34,-149.73,;76.8,-149.73,;82.55,-159.69,;94.05,-159.69,;99.8,-149.73,;94.05,-139.77,;82.55,-139.77,;48.12,-179.54,;25.17,-139.76,;13.71,-139.76,;7.98,-149.69,;13.71,-159.61,;7.98,-169.54,;-14.66,-169.54,;-26,-189.18,;-14.66,-208.79,;7.98,-208.79,;19.32,-189.18,;7.98,-129.84,;48.13,-139.77,)| AuxInfo=1/1/N:15,19,14,16,18,20,13,17,23,21,3,4,11,10,24,12,22,2,5,1,26,9,6,8,7,27,25/E:(3,4)(5,6)(7,8)(9,10)/it:im/rA:27nCC.eCCCNOONCCCCCCCCCCCCCCCOCO/rB:s1;s2;s3;s4;s1s5;d1;d5;N2;s6;s10;s11;d12;s13;d14;s15;s12d16;;d18;s19;d20;s21;s18d22;s22;s24;s9s25;d26;/rC:42,3977,-149,6966,0;30,9026,-149,6881,0;25,1477,-159,6446,0;30,8928,-169,6067,0;42,3928,-169,6124,0;48,1477,-159,6559,0;48,1277,-139,7719,0;48,1229,-179,5371,0;25,1726,-139,7634,0;59,6078,-159,6559,0;65,3378,-149,7312,0;76,7979,-149,7312,0;82,5479,-159,6905,0;94,0479,-159,6905,0;99,7979,-149,7312,0;94,0479,-139,7719,0;82,5479,-139,7719,0;7,9825,-208,7893,0;-14,6582,-208,7893,0;-25,9985,-189,1834,0;-14,6582,-169,5385,0;7,9825,-169,5375,0;19,3227,-189,1834,0;13,7125,-159,6128,0;7,9825,-149,6881,0;13,7125,-139,7634,0;7,9825,-129,8387,0; C21H22N2O4 C1=CC=C(C=C1)COC(=O)* Cbz CDK 04302613362D 0 0 0 0 0 999 V3000 M V30 BEGIN CTAB M V30 COUNTS 27 29 0 0 1 M V30 BEGIN ATOM M V30 1 C 42.39771 -149.69658 0 0 M V30 2 C 30.90262 -149.68811 0 0 CFG=1 M V30 3 C 25.14772 -159.64458 0 0 M V30 4 C 30.89284 -169.6067 0 0 M V30 5 C 42.39282 -169.61237 0 0 M V30 6 N 48.14772 -159.65588 0 0 M V30 7 O 48.12775 -139.77187 0 0 M V30 8 O 48.12286 -179.53708 0 0 M V30 9 N 25.17258 -139.7634 0 0 M V30 10 C 59.6078 -159.65588 0 0 M V30 11 C 65.33783 -149.73119 0 0 M V30 12 C 76.79791 -149.73119 0 0 M V30 13 C 82.54791 -159.69048 0 0 M V30 14 C 94.0479 -159.69048 0 0 M V30 15 C 99.79791 -149.73119 0 0 M V30 16 C 94.04791 -139.77188 0 0 M V30 17 C 82.54791 -139.77188 0 0 M V30 18 C 7.98245 -208.78929 0 0 M V30 19 C -14.65816 -208.78929 0 0 M V30 20 C -25.99846 -189.18338 0 0 M V30 21 C -14.65816 -169.53851 0 0 M V30 22 C 7.98245 -169.53754 0 0 M V30 23 C 19.32274 -189.18338 0 0 M V30 24 C 13.71249 -159.61282 0 0 M V30 25 O 7.98245 -149.68811 0 0 M V30 26 C 13.71249 -139.7634 0 0 M V30 27 O 7.98245 -129.83868 0 0 M V30 END ATOM M V30 BEGIN BOND M V30 1 1 1 2 M V30 2 1 2 3 M V30 3 1 3 4 M V30 4 1 4 5 M V30 5 1 5 6 M V30 6 1 6 1 M V30 7 2 1 7 M V30 8 2 5 8 M V30 9 1 6 10 M V30 10 1 10 11 M V30 11 1 11 12 M V30 12 2 12 13 M V30 13 1 13 14 M V30 14 2 14 15 M V30 15 1 15 16 M V30 16 2 16 17 M V30 17 1 17 12 M V30 18 1 2 9 CFG=3 M V30 19 2 18 19 M V30 20 1 19 20 M V30 21 2 20 21 M V30 22 1 21 22 M V30 23 2 22 23 M V30 24 1 18 23 M V30 25 1 22 24 M V30 26 1 24 25 M V30 27 1 25 26 M V30 28 2 26 27 M V30 29 1 9 26 M V30 END BOND M V30 END CTAB M END CZMNBXSJJDKRIU-OZXSUGGESA-N InChI=1S/C31H39N3O6/c1-3-23(2)30(38)34(21-27(35)32-19-10-15-29(37)40-22-25-13-8-5-9-14-25)26-16-17-28(36)33(31(26)39)20-18-24-11-6-4-7-12-24/h4-9,11-14,23,26H,3,10,15-22H2,1-2H3,(H,32,35)/t23-,26-/m0/s1 CC[C@H](C)C(=O)N(CC(=O)NCCCC(=O)OCC1=CC=CC=C1)[C@H]2CCC(=O)N(CCC3=CC=CC=C3)C2=O C1(=CC=CC=C1)CCN2C(CC[C@@H](C2=O)N(C([C@H](CC)C)=O)CC(NCCCC(=O)OCC3=CC=CC=C3)=O)=O |(165.04,-32.27,;175,-26.52,;175,-15.02,;165.04,-9.27,;155.09,-15.02,;155.09,-26.52,;165.04,-43.78,;155.08,-49.53,;155.08,-61.04,;165.04,-66.8,;165.04,-78.31,;155.08,-84.06,;145.11,-78.31,;145.11,-66.8,;135.14,-61.04,;135.14,-84.06,;125.18,-78.31,;115.21,-84.06,;105.24,-78.31,;95.28,-84.06,;115.21,-95.57,;125.18,-66.8,;135.14,-95.57,;145.11,-101.32,;155.08,-95.57,;165.04,-101.32,;175.01,-95.57,;184.98,-101.32,;194.94,-95.57,;194.94,-84.06,;204.91,-101.32,;204.91,-112.83,;214.88,-118.59,;214.88,-142.65,;235.73,-154.68,;256.58,-142.65,;256.58,-118.59,;235.73,-106.56,;145.11,-112.83,;175.01,-61.04,)| AuxInfo=1/1/N:21,22,18,4,34,3,5,33,35,40,2,6,32,36,38,11,12,7,39,8,27,37,19,1,31,10,25,13,28,20,9,24,14,17,26,16,29,23,15,30/E:(6,7)(8,9)(11,12)(13,14)/it:im/rA:40nCCCCCCCCCC.eCCCNOONCC.oCCCONCOCCOOCCCCCCCCCC/rB:d1;s2;d3;s4;s1d5;s1;s7;;s9;s10;s11;s12;s8s9s13;d9;d13;N10;;s18;s17s19;s18;P19;d20;;s24;d25;s17s25;;d28;s28;;d31;s32;d33;s34;s31d35;s30s31;s28;s24;s38s39;/rC:165,0445,-32,2712,0;175,0038,-26,5212,0;175,0038,-15,0212,0;165,0445,-9,2712,0;155,0852,-15,0212,0;155,0852,-26,5212,0;165,0445,-43,7798,0;155,0777,-49,5341,0;145,1109,-66,7971,0;145,1109,-78,3058,0;155,0777,-84,0602,0;165,0445,-78,3058,0;165,0445,-66,7971,0;155,0777,-61,0428,0;135,1441,-61,0428,0;175,0113,-61,0428,0;135,1441,-84,0602,0;105,2437,-78,3058,0;115,2105,-84,0602,0;125,1773,-78,3058,0;95,2769,-84,0602,0;115,2105,-95,5688,0;125,1773,-66,7971,0;155,0777,-95,5688,0;145,1109,-101,3232,0;145,1109,-112,8318,0;135,1441,-95,5688,0;194,9448,-95,5688,0;194,9448,-84,0602,0;204,9116,-101,3232,0;214,8784,-118,5861,0;214,8823,-142,6461,0;235,7304,-154,6760,0;256,5823,-142,6461,0;256,5823,-118,5861,0;235,7304,-106,5562,0;204,9116,-112,8318,0;184,9781,-101,3232,0;165,0445,-101,3232,0;175,0112,-95,5688,0; C31H39N3O6 C1=CC=C(C=C1)* Ph,C1=CC=C(C=C1)CO* OBn CDK 04302613362D 0 0 0 0 0 999 V3000 M V30 BEGIN CTAB M V30 COUNTS 40 42 0 0 1 M V30 BEGIN ATOM M V30 1 C 165.04446 -32.27116 0 0 M V30 2 C 175.00375 -26.52116 0 0 M V30 3 C 175.00375 -15.02116 0 0 M V30 4 C 165.04446 -9.27116 0 0 M V30 5 C 155.08517 -15.02116 0 0 M V30 6 C 155.08517 -26.52116 0 0 M V30 7 C 165.04446 -43.77982 0 0 M V30 8 C 155.07765 -49.53415 0 0 M V30 9 C 145.11087 -66.79715 0 0 M V30 10 C 145.11087 -78.30583 0 0 CFG=1 M V30 11 C 155.07765 -84.06015 0 0 M V30 12 C 165.04446 -78.30583 0 0 M V30 13 C 165.04446 -66.79715 0 0 M V30 14 N 155.07765 -61.04282 0 0 M V30 15 O 135.14407 -61.04282 0 0 M V30 16 O 175.01126 -61.04282 0 0 M V30 17 N 135.14407 -84.06015 0 0 M V30 18 C 105.24368 -78.30583 0 0 M V30 19 C 115.21048 -84.06015 0 0 CFG=2 M V30 20 C 125.17728 -78.30583 0 0 M V30 21 C 95.2769 -84.06015 0 0 M V30 22 C 115.21048 -95.56882 0 0 M V30 23 O 125.17728 -66.79715 0 0 M V30 24 N 155.07767 -95.56882 0 0 M V30 25 C 145.11087 -101.32315 0 0 M V30 26 O 145.11087 -112.8318 0 0 M V30 27 C 135.14407 -95.56882 0 0 M V30 28 C 194.94484 -95.56882 0 0 M V30 29 O 194.94484 -84.06015 0 0 M V30 30 O 204.91164 -101.32315 0 0 M V30 31 C 214.87843 -118.58614 0 0 M V30 32 C 214.88228 -142.64606 0 0 M V30 33 C 235.73036 -154.67603 0 0 M V30 34 C 256.58228 -142.64606 0 0 M V30 35 C 256.58228 -118.58614 0 0 M V30 36 C 235.73036 -106.55618 0 0 M V30 37 C 204.91164 -112.8318 0 0 M V30 38 C 184.97806 -101.32315 0 0 M V30 39 C 165.04446 -101.32315 0 0 M V30 40 C 175.01125 -95.56882 0 0 M V30 END ATOM M V30 BEGIN BOND M V30 1 2 1 2 M V30 2 1 2 3 M V30 3 2 3 4 M V30 4 1 4 5 M V30 5 2 5 6 M V30 6 1 1 6 M V30 7 1 1 7 M V30 8 1 7 8 M V30 9 1 9 10 M V30 10 1 10 11 M V30 11 1 11 12 M V30 12 1 12 13 M V30 13 1 13 14 M V30 14 1 14 9 M V30 15 2 9 15 M V30 16 2 13 16 M V30 17 1 10 17 CFG=3 M V30 18 1 14 8 M V30 19 1 18 19 M V30 20 1 19 20 M V30 21 1 18 21 M V30 22 1 19 22 CFG=1 M V30 23 2 20 23 M V30 24 1 24 25 M V30 25 2 25 26 M V30 26 1 20 17 M V30 27 1 17 27 M V30 28 1 27 25 M V30 29 2 28 29 M V30 30 1 30 37 M V30 31 2 31 32 M V30 32 1 32 33 M V30 33 2 33 34 M V30 34 1 34 35 M V30 35 2 35 36 M V30 36 1 31 36 M V30 37 1 31 37 M V30 38 1 28 30 M V30 39 1 28 38 M V30 40 1 24 39 M V30 41 1 39 40 M V30 42 1 40 38 M V30 END BOND M V30 END CTAB M END GGJFNBLKHRDMGW-UHFFFAOYSA-N InChI=1S/C12H13NO2/c1-13-9-5-8-12(14)15-10-11-6-3-2-4-7-11/h2-4,6-7H,5,8-10H2 [C-]#[N+]CCCC(=O)OCC1=CC=CC=C1 [N+](#[C-])CCCC(=O)OCC1=CC=CC=C1 |(23.13,-57.94,;34.64,-57.94,;33.06,-63.68,;43.02,-57.93,;52.99,-63.68,;62.96,-57.93,;62.96,-46.42,;62.15,-60.79,;56.4,-50.83,;44.89,-50.83,;39.13,-40.86,;27.62,-40.86,;21.87,-50.83,;27.62,-60.79,;39.13,-60.79,)| AuxInfo=1/0/N:2,10,9,11,14,8,12,15,3,13,7,4,1,5,6/E:(3,4)(6,7)/CRV:1-1,13+1/rA:15nN+C-CCOOCCCCCCCCC/rB:t1;s1;;d4;s4;;d7;s8;d9;s10;s7d11;s6s7;s3;s4s14;/rC:23,1279,-57,9371,0;34,6366,-57,9371,0;33,0573,-63,6814,0;62,9577,-57,9271,0;62,9577,-46,4184,0;62,1493,-60,7942,0;44,8863,-50,8275,0;39,1320,-40,8607,0;27,6233,-40,8607,0;21,8690,-50,8275,0;27,6233,-60,7943,0;39,1320,-60,7943,0;56,3950,-50,8275,0;43,0241,-57,9271,0;52,9909,-63,6814,0; C12H13NO2 [C-]#[N+]* NC,C1=CC=C(C=C1)CO* OBn CDK 04302613362D 0 0 0 0 0 999 V3000 M V30 BEGIN CTAB M V30 COUNTS 15 15 0 0 0 M V30 BEGIN ATOM M V30 1 N 23.12791 -57.93713 0 0 CHG=1 M V30 2 C 34.63657 -57.93713 0 0 CHG=-1 M V30 3 C 33.0573 -63.68144 0 0 M V30 4 C 62.95769 -57.92711 0 0 M V30 5 O 62.95769 -46.41844 0 0 M V30 6 O 62.14934 -60.79424 0 0 M V30 7 C 44.88634 -50.82745 0 0 M V30 8 C 39.132 -40.86066 0 0 M V30 9 C 27.62334 -40.86066 0 0 M V30 10 C 21.869 -50.82745 0 0 M V30 11 C 27.62334 -60.79425 0 0 M V30 12 C 39.132 -60.79425 0 0 M V30 13 C 56.395 -50.82745 0 0 M V30 14 C 43.02409 -57.92711 0 0 M V30 15 C 52.99089 -63.68144 0 0 M V30 END ATOM M V30 BEGIN BOND M V30 1 3 1 2 M V30 2 1 1 3 M V30 3 2 4 5 M V30 4 1 6 13 M V30 5 2 7 8 M V30 6 1 8 9 M V30 7 2 9 10 M V30 8 1 10 11 M V30 9 2 11 12 M V30 10 1 7 12 M V30 11 1 7 13 M V30 12 1 4 6 M V30 13 1 3 14 M V30 14 1 14 15 M V30 15 1 15 4 M V30 END BOND M V30 END CTAB M END Experimental procedures and analytical data. <chunk>Acknowledgements</chunk> The authors thank Dr. Jürgen Schmidt and Mr. Torsten Geißler for the HRMS and emission spectra and Ms. Leah M. Harris for a kind revision of this manuscript. R.A.W.N.F. is grateful to CNPq for a Ph.D. fellowship. Mol. Diversity Asoc. Quim. Argent. Fitoterapia Nat. Prod. Res. Tetrahedron Lett. J. Org. Chem. Int. J. Quantum Chem. Parasitol. Res. Leishmaniasis: The magnitude of the problem, World Health Organization. http://www.who.int/leishmaniasis/burden/magnitude/burden_magnitude/en/index.html (accessed July 25, 2011). Med. Hypotheses Tetrahedron Lett. Arch. Pharmacal Res. Arch. Pharmacal Res. and references cited therein J. Nat. Prod. Chin. J. Chem. During the preparation of this manuscript the above mentioned article, applying a similar strategy for the synthesis of (−)-julocrotine, was published. Bioorg. Med. Chem. Lett. J. Am. Chem. Soc. Synthesis Drug Dev. Res. Synlett This is an Open Access article under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The license is subject to the Beilstein Journal of Organic Chemistry terms and conditions: (http://www.beilstein-journals.org/bjoc)