Identification of the new prenyltransferase Ubi-297 from marine bacteria and elucidation of its substrate specificity

• Jamshid Amiri Moghaddam,
• Huijuan Guo,
• Karsten Willing,
• Thomas Wichard and
• Christine Beemelmanns

Beilstein J. Org. Chem. 2022, 18, 722–731, doi:10.3762/bjoc.18.72

• quantification: Plasmids containing the respective gene were transformed into E. coli BL21 and strains harboring the plasmid were cultivated in TB medium supplemented with kanamycin (60 µg mL−1). Cultures were grown at 37 °C to an OD600 of 0.8, then brought to 16 °C and isopropyl β-ᴅ-thiogalactoside (IPTG) was

Bioinspired tetraamino-bisthiourea chiral macrocycles in catalyzing decarboxylative Mannich reactions

• Hao Guo,
• Yu-Fei Ao,
• De-Xian Wang and
• Qi-Qiang Wang

Beilstein J. Org. Chem. 2022, 18, 486–496, doi:10.3762/bjoc.18.51

• linking components to afford Lewis base sites and also for introduction of chirality. Different alkyl substituents including methyl, n-propyl, isopropyl, and 3-pentyl were incorporated in order to tune the size and steric effect of the macrocyclic cavity and thus to enable diverse cavity environments

• on the reaction stereoselectivity. The cyclohexanediamine-linking macrocycles M1–M4 afforded the product with overall higher enantiomeric excess (ee) (Table 1, entries 1–4). Among which the isopropyl-substituted macrocycle M3 gave the best selectivity, i.e., 42% ee. This suggested a suitable crowding

Sesquiterpenes from the soil-derived fungus Trichoderma citrinoviride PSU-SPSF346

• Wiriya Yaosanit,
• Vatcharin Rukachaisirikul,
• Souwalak Phongpaichit,
• Sita Preedanon and
• Jariya Sakayaroj

Beilstein J. Org. Chem. 2022, 18, 479–485, doi:10.3762/bjoc.18.50

• , s, 2H), three sets of nonequivalent methylene protons (δH 3.40 and 3.30, each d, J = 16.8 Hz, 1H; δH 2.13 and 2.04, each m, 1H; δH 1.81 and 1.39, each m, 1H), and an isopropyl group (δH 1.71, m, 1H, and δH 0.95 and 0.82, each d, J = 6.9 Hz, 3H). The 13C NMR spectrum (Table 1) consisted of signals

• and 1.37, m, 1H; δH 1.84 and 1.64, each m, 1H), and an isopropyl group (δH 1.83, m, 1H, and δH 1.06 and 0.88, each d, J = 6.5 Hz, 3H). The 13C NMR spectrum (Table 1) consisted of signals for two carboxyl carbonyl carbons (δC 179.6 and 174.5), two quaternary carbons (one olefinic carbon, δC 150.2, and

• (δH 2.81), H-5/H-10 (δH 1.35), and Hab-9 (δH 1.84 and 1.64)/Hab-8 (δH 2.45 and 1.37) and H-10, and the HMBC correlations (Figure 2) from H3-12 (δH 1.06) and H3-13 (δH 0.88) of the isopropyl group to C-10 (δC 49.0) and Hab-15 (δH 3.69 and 3.65) to C-6 (δC 51.4), C-7 (δC 83.4), and C-8 (δC 29.3) as well

The asymmetric Henry reaction as synthetic tool for the preparation of the drugs linezolid and rivaroxaban

• Martin Vrbický,
• Karel Macek,
• Jaroslav Pochobradský,
• Jan Svoboda,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2022, 18, 438–445, doi:10.3762/bjoc.18.46

• performed on sub-millimolar scales in isopropyl alcohol (IPA). The obtained products 21–26 were separated from the starting aldehydes 15–20 by column chromatography. The reaction conditions (i.e., temperature, reaction time, amount of catalyst, and solvent) were adopted from the pilot study [12] for

Flow synthesis of oxadiazoles coupled with sequential in-line extraction and chromatography

• Kian Donnelly and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 232–239, doi:10.3762/bjoc.18.27

• ]pentane (BCP) building blocks [36], we investigated their use in the oxadiazole-forming reaction. The BCP acid chloride 5 was synthesised from [1.1.1]propellane (3) via the photochemical reaction with isopropyl 2-chloro-2-oxoacetate (Scheme 4). The corresponding BCP acyl hydrazone was then obtained

Anomeric 1,2,3-triazole-linked sialic acid derivatives show selective inhibition towards a bacterial neuraminidase over a trypanosome trans-sialidase

• Peterson de Andrade,
• Sanaz Ahmadipour and
• Robert A. Field

Beilstein J. Org. Chem. 2022, 18, 208–216, doi:10.3762/bjoc.18.24

• ). Incubation at 37 °C along with shaking (200 rpm) was continued until optical density (OD600) reached 0.6. Heterologous protein expression was induced by adding isopropyl β-ᴅ-1-thiogalactopyranoside (IPTG) to a final concentration of 1 mM and incubating for 4 hours at 30 °C with shaking (180 rpm). The cells

Unsaturated fatty acids and a prenylated tryptophan derivative from a rare actinomycete of the genus Couchioplanes

• Shun Saito,
• Kanji Indo,
• Naoya Oku,
• Hisayuki Komaki,
• Masashi Kawasaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2939–2949, doi:10.3762/bjoc.17.203

• . The 1H NMR spectrum of 2 was similar to those of 1 in overall (Table 1 and Table 2). One major difference was a replacement of the triplet methyl peak in 1 by a six proton-equivalent doublet methyl peak, which suggested an isopropyl-terminated structure. This was proven by a COSY correlation between

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

• Viera Poláčková,
• Dominika Krištofíková,
• Boglárka Némethová,
• Renata Górová,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

• ratio of 86:14 and high enantiomeric purity of 95:5 er for the major diastereomer (Table 1, entry 1). Using chloroform/isopropyl alcohol 9:1 as the solvent mixture afforded after 120 hours, aldehyde 10a in 45% yield with 83:17 dr and 97:3 er (Table 1, entry 2). The Michael addition in methanol catalyzed

Allylic alcohols and amines by carbenoid eliminative cross-coupling using epoxides or aziridines

• Matthew J. Fleming and
• David M. Hodgson

Beilstein J. Org. Chem. 2021, 17, 2385–2389, doi:10.3762/bjoc.17.155

• stereoselectivity. However, neither isopropyl or neopentyl benzylic ethers 26 and 27 [23][24] led to a significant change in the E/Z ratio for cinnamylamine 23 (Scheme 11). Conclusion In summary, we report a new, convergent access to allylic alcohols and amines. The process proceeds by selective cross-coupling of α

• epoxide 5. Synthesis of vinylsilane 14. Allylic alcohol 8 from epoxide 5 and sulfone 15. Allylic amines from aziridine 17. Cyclopropylidene synthesis from aziridine 20. Cinnamylamine 23 synthesis from aziridine 17. Cinnamylamine 23 synthesis from isopropyl or neopentyl benzylic ethers 26 and 27

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

• Sumana Mandal,
• Raju D. Chaudhari and
• Goutam Biswas

Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153

• piperidine derivatives were also synthesized by Hg(II)-salt-induced cyclization. N-Isopropyl-1-aminohex-4-ene (23) on treatment with 1 equiv HgCl2 followed by reduction with NaBH4 yielded pyrrolidine 24 and piperidine derivative 25 in the ratio of 7:3 [50]. N-Methylaniline derivative 26 undergoes cyclization

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

• macromolecule is in solution. The best known example of a phase transition with an LCST is PNIPAAm with its hydrophilic isopropyl groups interacting with water molecules [48][97][98][99]. From a thermodynamic point of view, the hydrogen bonds between the polymer and the water molecules lead to a negative value

Preparation of mono-substituted malonic acid half oxyesters (SMAHOs)

• Tania Xavier,
• Sylvie Condon,
• Christophe Pichon,
• Erwan Le Gall and
• Marc Presset

Beilstein J. Org. Chem. 2021, 17, 2085–2094, doi:10.3762/bjoc.17.135

• step, the opening of the Meldrum's acid moiety with an alcohol 8. Indeed, this reaction was achieved under simple conditions and led to the desired products in useful yields, only limited by partial in situ decarboxylation. This strategy thus allowed the preparation of the isopropyl (4ch, 93%) and

Enantioenriched α-substituted glutamates/pyroglutamates via enantioselective cyclopropenimine-catalyzed Michael addition of amino ester imines

• Zara M. Seibel,
• Jeffrey S. Bandar and
• Tristan H. Lambert

Beilstein J. Org. Chem. 2021, 17, 2077–2084, doi:10.3762/bjoc.17.134

• isopropyl completely suppressed reactivity (Table 2, entry 8). On the other hand, allyl (Table 2, entry 9) and propargyl (Table 2, entry 10) groups proved to viable substituents, leading to the products in good yield and high enantioselectivities. Of course, these two functional groups provide convenient

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

• attention. Nevertheless, β(1–6)-linked GlcN oligosaccharides may act as potential antitumor and immunostimulating agents [262] and could become important synthetic targets. The synthesis of a β(1–6)-linked 9mer was demonstrated, using an isopropyl thioglycoside donor [262]. Convergent [262] as well as

Fritsch–Buttenberg–Wiechell rearrangement of magnesium alkylidene carbenoids leading to the formation of alkynes

• Tsutomu Kimura,
• Koto Sekiguchi,
• Akane Ando and
• Aki Imafuji

Beilstein J. Org. Chem. 2021, 17, 1352–1359, doi:10.3762/bjoc.17.94

• )-substituted 1-chlorovinyl p-tolyl sulfoxide 2a was added to isopropylmagnesium chloride in toluene at −78 °C, and the mixture was warmed to 0 °C for 2 h (Table 1, entry 1). Excess isopropylmagnesium chloride (3.5 equivalents) was necessary for the complete consumption of the sulfoxide. As a result, isopropyl

• isopropylmagnesium chloride in 99% yield (Table 2, entry 1). In contrast, the treatment of 2,2-dialkyl-substituted sulfoxide 2c with isopropylmagnesium chloride gave a complex mixture including alkene 11 with an isopropyl group, which arose from the SNV reaction, in 35% yield (Table 2, entry 2, and Scheme 5). To

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Heterogeneous photocatalytic cyanomethylarylation of alkenes with acetonitrile: synthesis of diverse nitrogenous heterocyclic compounds

• Guanglong Pan,
• Qian Yang,
• Wentao Wang,
• Yurong Tang and
• Yunfei Cai

Beilstein J. Org. Chem. 2021, 17, 1171–1180, doi:10.3762/bjoc.17.89

• , delivering the corresponding regioisomers 8l and 8l’ in 62% with 1:1.6 ratio. Moreover, the naphthalene and tetrahydroisoquinoline-derived acrylamides were also compatible, giving the polycyclic products 8m and 8n in 77% and 70%, respectively. Additionally, protecting groups such as isopropyl, benzyl, or

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

• t-BuOH and LiBr as additives [102]. The isopropyl-substituted derivative 84 was easily converted into the corresponding methylene lactam 85, upon removal of the sulfinyl unit under acidic conditions. Finally, ozonolysis of 85 yielded tetramic acid 86 in 60% yield (Scheme 26). The configuration of

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• derivatives were 2 equivalents of dicyandiamide and 2.2 equivalents of trimethylsilyl chloride in dry acetonitrile under MW irradiation (200–400 W) for 15 min at 140 °C. As for the work-up, the authors described that after cooling of the reaction mixture, dilution with isopropyl alcohol (3 equivalents) and

Amino- and polyaminophthalazin-1(2H)-ones: synthesis, coordination properties, and biological activity

• Zbigniew Malinowski,
• Emilia Fornal,
• Agata Sumara,
• Renata Kontek,
• Karol Bukowski,
• Beata Pasternak,
• Dariusz Sroczyński,
• Joachim Kusz,
• Magdalena Małecka and
• Monika Nowak

Beilstein J. Org. Chem. 2021, 17, 558–568, doi:10.3762/bjoc.17.50

• selectively alkylated on the nitrogen atom [30][36]. For our purposes, the simple alkyl halides (MeI, iPrI), and 2-chloro-N,N-dimethylethylamine hydrochloride and 4-(2-chloroethyl)morpholine hydrochloride, were chosen as the alkylating agents. Thus, the desired N-methyl and N-isopropyl lactams 3a,b (3a R1

• = Me, 85%; 3b R1 = iPr, 84%) were obtained by the direct alkylation of bromophthalazinone 2 with methyl or isopropyl iodide in the presence of K2CO3 in dry acetone as the solvent (conventional heating). In the similar way also the 2-aminoethyl lactams 3c (R1 = CH2CH2NMe2) and 3d (R1 = CH2CH2(morpholin

• In conclusion, we have demonstrated an efficient synthesis of 2-substituted (alkyl, aminoalkyl) 4-aminophthalazinones 5 and 6 via the direct bromination of phthalazin-1(2H)-one (1) with potassium tribromide, followed by the alkylation of 4-bromophthalazinone 2 with methyl iodide, isopropyl iodide or

Menthyl esterification allows chiral resolution for the synthesis of artificial glutamate analogs

• Kenji Morokuma,
• Shuntaro Tsukamoto,
• Kyosuke Mori,
• Kei Miyako,
• Ryuichi Sakai,
• Raku Irie and
• Masato Oikawa

Beilstein J. Org. Chem. 2021, 17, 540–550, doi:10.3762/bjoc.17.48

• CONFLEX, as follows. Thus, as for 21* (see Figure 7), three characteristic NOESY crosspeaks observed between isopropyl protons and methyl ester protons (MeA/MeB, MeA/MeC, MeA/HD) were found to be reasonably accounted for by the top 5 stable conformers (89.9% total population) calculated for the (2S

• , surrounded by a purple square (Figure 9), are preferably in a linear zigzag arrangement, 2) the dihedral angle of O–C–CH2–C, shown in red color, is preferably 180°, and 3) on the other hand, a steric repulsion, shown in blue color, seems to occur between the isopropyl group and the methyl ester. For the (R

• steric repulsion with the large ring C with the TFA group, the isopropyl group takes a conformation proximal to the methyl ester (see Figure 7). For 10*, with smaller size of the ring C, a conformer in which the isopropyl group and the methyl ester are separated also seems to be energetically

1,2,3-Triazoles as leaving groups in S_NAr–Arbuzov reactions: synthesis of C6-phosphonated purine derivatives

• Kārlis-Ēriks Kriķis,
• Irina Novosjolova,
• Anatoly Mishnev and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 193–202, doi:10.3762/bjoc.17.19

• to optimize the Cl→N3 SNAr process at the purine C2 position, and that way, the isopropyl phosphonate 2b was also obtained. It is known that both chloride and azide can cleave phosphonate esters [25][26][27][28], but the chloride source would not interfere with the SNAr process at C2. Hence, we

• Supporting Information File 1). The cleavage of the ester groups in the presence of NaCl was slower than in the presence of NaN3 (Figure 1 and Table S2 in Supporting Information File 1). Further, the cleavage of the sterically bulky isopropyl ester from phosphonate 2b showed a similar pattern: 5

Facile preparation and conversion of 4,4,4-trifluorobut-2-yn-1-ones to aromatic and heteroaromatic compounds

• Takashi Yamazaki,
• Yoh Nakajima,
• Minato Iida and
• Tomoko Kawasaki-Takasuka

Beilstein J. Org. Chem. 2021, 17, 132–138, doi:10.3762/bjoc.17.14

• (that is, one of the two methyl groups in acetylacetone was formally substituted for an isopropyl or a t-Bu moiety, respectively), but no reaction was observed at all. The conjugate addition of amines to this type of ynone has already been reported [21], where the authors pointed out the significant

On the mass spectrometric fragmentations of the bacterial sesterterpenes sestermobaraenes A–C

• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2020, 16, 2807–2819, doi:10.3762/bjoc.16.231

• originating from the isopropyl group C20–19–21 or, by involving multiple C–C bond cleavages and hydrogen rearrangements, from the C25–3–4 portion. Alternatively, a combined loss of the C8–9 moiety and one methyl group (C22, C23, C24, or C25) is possible which basically combines the fragmentations of Scheme 1A

• and Scheme 1B. The loss of the isopropyl group C20–19–21 can be achieved by an inductive cleavage of 1•+ to g1•+ followed by an α-cleavage to h1+ (Scheme 1D). Starting from c1•+, two α-cleavages with the extrusion of ethylene can lead to i1•+ that upon a third α-fragmentation with loss of the methyl

• to f2•+ (Scheme 3C). Also for compound 2 different mechanisms for the formation of the fragment ion at m/z = 297 are observed, including the loss of the isopropyl group C20–19–21 or the loss of C8–9 and one methyl group. The cleavage of the isopropyl group is possible from c2•+ by an inductive ring

Encrypting messages with artificial bacterial receptors

• Pragati Kishore Prasad,
• Naama Lahav-Mankovski,
• Leila Motiei and
• David Margulies

Beilstein J. Org. Chem. 2020, 16, 2749–2756, doi:10.3762/bjoc.16.225

• supplemented with 100 μg/mL of ampicillin at 30 °C. Then, the pre-cultured cells were diluted 1:100 in fresh LB medium supplemented with the same concentration of ampicillin, and incubated until the OD600 reached ≈0.6. In order to induce protein expression, 0.1% rhamnose and 20 μM isopropyl-β-ᴅ-1