Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

• Yordanka Mollova-Sapundzhieva,
• Plamen Angelov,
• Danail Georgiev and
• Pavel Yanev

Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132

• the nitro group with subsequent cyclization of the reduced intermediate (Scheme 2, conditions iv). We tried to carry out these reactions either with Zn in acetic acid/dichloromethane or by transfer hydrogenation with ammonium formate in the presence of Pd on charcoal. Both types of reductive

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• colleagues reported on the photocatalytic decarboxylative alkenylation reactions facilitated by cooperative NaI/PPh3 catalysis [9]. These conversions involved the coupling of 1,1-diarylethene/cinnamic acid derivatives (1, 2) with redox-active esters 3 (Scheme 3). Notably, the reactions were driven by blue

Active-metal template clipping synthesis of novel [2]rotaxanes

• Cătălin C. Anghel,
• Teodor A. Cucuiet,
• Niculina D. Hădade and
• Ion Grosu

Beilstein J. Org. Chem. 2023, 19, 1776–1784, doi:10.3762/bjoc.19.130

• acid (HEEDTA) saturated solution (3 × 20 mL), water and brine. After drying on MgSO4 the solvent was evaporated. The compound was purified by column chromatography (silica, acetone/methanol = 20:1, Rf = 0.33) to afford a white solid (45 mg, 20%). Rf = 0.33 (silica, acetone/methanol = 20:1 v/v). 1H NMR

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• transition-metal-based complexes, the outcomes are generally two-electron reduction products, such as carbon monoxide (CO), formic acid (HCO2H), or formate (HCO2−). To mitigate the strong energetic requirements of the reaction shown in Equation 1, the reduction of CO2 occurs in the presence of protons, so

• that the energy barriers of the reactions shown in Equation 2 and Equation 3 are lowered. In fact, the formation of the radical anion CO2−· takes place at −1.9 V versus normal hydrogen electrode (NHE), while the proton-assisted reductions of CO2 to CO and formic acid happen at −0.53 V and −0.61 V

Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks

• Zhang Dongxu

Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127

• presence of Brønsted acid. In their pioneering research, Tanaka et al. reported the [3 + 2] cycloaddition reactions of trifluoroacetaldehyde hydrazones and glyoxals to give 4-hydroxy-3-trifluoromethylpyrazoles. The resultant pyrazoles containing a free 4-hydroxy group were easily converted to a variety of

• conditions [38] (Scheme 2). Moreover, a chiral Brønsted acid-catalyzed asymmetric 6π electrocyclization of trifluoroacetaldehyde hydrazones for the synthesis of enantiomerically enriched 3-trifluoromethyl-1,4-dihydropyridazines was first developed by Rueping et al. [39]. The strategy involves chiral ion

• pairs and provides a good basis and scope for further extensions and explorations [39] (Scheme 3). Based on the work by Wu et al. and extending their previous work, Rueping and co-workers explored the effects of fluorine in organocatalytic reactions. They developed an asymmetric Brønsted acid–Lewis base

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• derived from 3,4,5-trimethoxybenzoic acid hydrazide, a modification inspired by mescaline, the active principle of the hallucinogenic cactus peyote, which could result in a greater BBB penetration [36]. In this study, however, the structural modifications in the compound did not seem to significantly

• derived from the same 3,4,5-trimethoxybenzoic acid hydrazide, but differ with respect to the carbonyl precursors: herein, 3-substituted salicylaldehydes (Scheme 1) are used, which assure for a harder donor-atoms set in order to target trivalent metal ions such as aluminum(III), which has been proposed to

• -Aldrich and Vetec in the highest purity available and used without further purification. Syntheses of the compounds Compounds were synthesized by modifying the existing methodology in the literature [50]. The compounds were prepared by condensation between 3,4,5-trimethoxybenzoic acid hydrazide (TMP, 1.0

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• phenyl-C61-butyric acid methyl ester (PCBM) acceptor when used in bulk heterojunction polymer solar cell devices with poly(3-hexylthiophene) (P3HT) as the donor material. This improvement was attributed to the anchoring effect of the bulkier groups present in TQT-C60, which hindered the movement and

Decarboxylative 1,3-dipolar cycloaddition of amino acids for the synthesis of heterocyclic compounds

• Xiaofeng Zhang,
• Xiaoming Ma and
• Wei Zhang

Beilstein J. Org. Chem. 2023, 19, 1677–1693, doi:10.3762/bjoc.19.123

• with arylaldehydes are much less explored. The [3 + 2] adducts of α-amino acids could be used for a second [3 + 2] cycloaddition as well as for other post-condensation modifications. This article highlights our recent work on the development of α-amino acid-based [3 + 2] cycloaddition reactions of N–H

• stereoselectivity which limits the synthetic utility of non-stabilized AMYs of type C. There are over 300 papers on the amino acid-based decarboxylative [3 + 2] cycloadditions of N–R-type AMYs B1 (such as that derived from proline) and B2 [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49

• aldehydes and alkenes. The first cycloaddition products 3c or 3d can also be used as intermediates for other transformations to synthesize novel heterocyclic rings via multicomponent, one-pot, and stepwise synthesis [63][64]. Presented in the following sections is our work on the development of amino acid

Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

• Swagat K. Mohapatra,
• Khaled Al Kurdi,
• Samik Jhulki,
• Georgii Bogdanov,
• John Bacsa,
• Maxwell Conte,
• Tatiana V. Timofeeva,
• Seth R. Marder and
• Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

• , for example through hydride abstraction by Ph3C+ [13]. Alternatively, they can also be obtained by condensation of N,N'-dimethylphenylene-1,2-diamine derivatives with acid chlorides, YCOCl, or through the methylation of 2-substituted benzoimidazoles [24], which in turn can be obtained from

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• with trifluoroacetic acid (TFA) resulted in a cationic 40-H+. Cyclic voltammetry and differential pulse voltammetry were performed to investigate the electrochemical properties of 40-H+. The cation exhibited two reversible oxidations and two to three reductions. The redox potentials were influenced by

• complexes, the fragment originating from the porphyrinoid could form hydrogen bonds with a carboxyl group, while the crown ether cavity would allow interaction with the protonated amine group of an amino acid molecule. The choice of macrocycle size could enable the recognition of different biomolecules

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

• Ken-ichi Nakashima,
• Naohito Abe,
• Masayoshi Oyama,
• Hiroko Murata and
• Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

• potential anti-inflammatory activity. In this study, three new sulfur-containing spiroketals – breynin J (1), epibreynin J (2), and probreynogenin (3) – along with four known compounds – probreynin I (4), phyllaemblic acid (5), breynin B (6), and epibreynin B (7) – were isolated from the roots of Breynia

• glycosides [1][2][3], flavan-3-ol glycosides [4], alkaloids [5], and phenolic glycosides [5][6]. Notably, sulfur-containing spiroketal glycosides, represented by breynins and epibreynins, have characteristic sesquiterpenoid-derived structures. The sesquiterpenoid phyllaemblic acid and its glycosides, which

• four known spiroketals – probreynin I (4) [13], phyllaemblic acid (5) [10], breynin B (6) [2], and epibreynin B (7) [2] – from the roots of B. disticha, a species that has not previously been chemically investigated (Figure 1). Herein, we describe the isolation and structural elucidation of new

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• . Polyacrylonitrile (PAN), polyacrylic acid (PAA), and polyacrylamide (PAM), for instance, are obtained by solution polymerization in the polymer industry [23][24][25]. In addition to the reduced reaction rate due to lower monomer and initiator concentrations, one of the major disadvantages of solution polymerization

• photooxidation of polystyrene in the presence of FeCl3 as a radical source (Scheme 21a) [202]. A molar yield of 23% benzoyl small molecules was achieved. Reisner and co-workers employed a similar approach but using aromatic ketones as photocatalyst (Scheme 21b) [203]. Benzoic acid and other aromatic small

• amino acid sequence of mfp-1, mfp-3, and mfp-5 (Y: DOPA, K: lysine). B) Scheme showing examples of the adhesive and cohesive properties of catechol-containing proteins. R represents the remainder of the mfp’s. Scheme 3 redrawn from [10]. Activation–deactivation equilibrium in nitroxide-mediated

Cyclodextrins permeabilize DPPC liposome membranes: a focus on cholesterol content, cyclodextrin type, and concentration

• Ghenwa Nasr,
• Hélène Greige-Gerges,
• Sophie Fourmentin,
• Abdelhamid Elaissari and
• Nathalie Khreich

Beilstein J. Org. Chem. 2023, 19, 1570–1579, doi:10.3762/bjoc.19.115

• sulforhodamine B were purchased from Sigma-Aldrich, USA. 4-Amino-3-hydroxy-1-naphthalene sulfonic acid was purchased from Fluka, India. Sulfuric acid was purchased from ACROS Organics, Belgium and diethyl ether was purchased from VWR-Prolabo Chemicals, Belgium. Liposomes preparation, extrusion, and purification

C–H bond functionalization: recent discoveries and future directions

• Indranil Chatterjee

Beilstein J. Org. Chem. 2023, 19, 1568–1569, doi:10.3762/bjoc.19.114

• its combination with organometallic chemistry for site-selective C−H bond functionalization [3][4]. Recent years have witnessed many viable strategies for the synthesis of complex targets utilizing photoredox catalysis, electroorganic catalysis, Lewis acid catalysis, and transition-metal-free

Lewis acid-promoted direct synthesis of isoxazole derivatives

• Dengxu Qiu,
• Chenhui Jiang,
• Pan Gao and
• Yu Yuan

Beilstein J. Org. Chem. 2023, 19, 1562–1567, doi:10.3762/bjoc.19.113

• nitrite as a nitrogen-oxygen source, and solely using aluminum trichloride as the additive. This approach circumvents the need for costly or highly toxic transition metals and presents a novel pathway for the synthesis of isoxazole derivatives. Keywords: aluminum trichloride; Lewis acid; isoxazole

• the Lewis acid to realize the sp3 C–H-bond activation of nitrogen heterocycles to synthesize isoxazole derivatives. Results and Discussion At the outset of this study, we chose the reaction of 2-methylquinoline (2a) with phenylacetylene (1a) in the presence of AlCl3 (3 equiv) and sodium nitrite (10

• complexed with the starting material 2a to generate intermediate B and HONO [22]. Then, the intermediate B conjugates with HONO to generate intermediate C [22]. Next, the intermediate D is produced by the same progress. The intermediate D then undergoes elimination of nitroxylic acid to produce nitrile

Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

• Bel Youssouf G. Mountessou,
• Élodie Gisèle M. Anoumedem,
• Blondelle M. Kemkuignou,
• Yasmina Marin-Felix,
• Frank Surup,
• Marc Stadler and
• Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

• acetic acid (data not shown), we can exclude that it is an isolation artefact. The fifteen known compounds isolated from Diaporthe cameroonensis extract, which included alternariol (3) [14], 2-hydroxyalternariol (4) [15], 4-hydroxyalternariol (5) [16][17], 2,5-dimethyl-7-hydroxychromone (6) [18

• sulfuric acid before heating. LC–MS chromatograms were recorded with an UltiMate 3000 Series uHPLC (Thermo Fischer Scientific) using a C18 Acquity UPLC BEH column (2.1 × 50 mm, 1.7 µm) connected to an amazon speed ESI-Iontrap-MS (Bruker). Semi-preparative and/or preparative HPLC systems on normal and

• -VAP Expert, Germany). HRESIMS spectra were recorded with an Agilent 1200 Infinity Series HPLC-UV system (Agilent Technologies; column 2.1 × 50 mm, 1.7 µm, C18 Acquity UPLC BEH (waters), solvent A: H2O + 0.1% formic acid; solvent B: ACN + 0.1% formic acid, gradient: 5% B for 0.5 min increasing to 100

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

• Tzu-Yu Huang,
• Mario Djugovski,
• Sweta Adhikari,
• Destinee L. Manning and
• Sudeshna Roy

Beilstein J. Org. Chem. 2023, 19, 1545–1554, doi:10.3762/bjoc.19.111

• ≈ 25.8) [34], facilitates the direct deprotonation of morpholine as opposed to acting as a scavenger base. Due to the significant difference in pKa values between the conjugate acids of morpholine (pKa of the conjugate acid is 8.3) [35] and LiHMDS, we posit that LiHMDS directly deprotonates morpholine

• different Li+ source (LiCl, 0.1 equiv) with a weaker base (Cs2CO3, pKa of the conjugate acid 10.3) [36], it afforded the product in 29% yield, which is much poorer than under the previously optimized conditions (see Supporting Information File 1, Table S1). This observation suggests that Li+ ions act as a

Synthesis of 5-arylidenerhodanines in L-proline-based deep eutectic solvent

• Stéphanie Hesse

Beilstein J. Org. Chem. 2023, 19, 1537–1544, doi:10.3762/bjoc.19.110

• Knoevenagel condensation is well documented [21]. Moreover, the low cost and high availability of ʟ-proline has attracted attention to ʟ-proline-based DES. Especially, in 2022, Detsi [20] has synthesized and characterized three ʟ-proline-based NaDES: proline/oxalic acid (1:1), proline/glycerol (1:2), and

• proline/lactic acid/water (1:2:2.5). The authors studied their use in the synthesis of aurones via a Knoevenagel condensation and compared them to the classical choline-based DES, ChCl/Gly (1:2). They demonstrated that the ʟ-proline-based DES were superior to ChCl/Gly and obtained aurones from the

• . Surprisingly, 2-naphthaldehyde was found to be less reactive and needed a reaction time of 24 h to obtain product 3g with 85% yield. Heterocyclic aldehydes gave also good results as shown with pyrrole-2-carboxaldehyde that allowed formation of product 3h in 86% yield. Rhodanine-3-acetic acid also allowed

Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• , followed by cyclization with glyoxal in formic acid. We then wished to slightly perturb the electron density via introduction of fluorine (either at R1 or R3), but it was at this time that an unexpected result was observed. Following the same conditions which produced B1, NMR evaluation of our next product

• of two substituted arylboronic acids, followed by N-methylation, and final ring-closure via Bischler–Napieralski conditions [45][47][48]. These steps provided chelerythrine variants C1–C4, with structural variability stemming from the initial substituted tetralone (R1/R2) and/or the arylboronic acid

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• -catalyzed sulfenylation by N-(sulfenyl)succinimides/phthalimides In 2012, Chen and co-workers found that in the reaction of N-(organothio)succinimides 1 and sodium sulfinates 2 using a Lewis acid in ionic liquids (ILs) and water as a green solvent system leads to the formation of thiosulfonates 3 (Scheme 2

• ) [44]. Among different Lewis acid catalysts, such as Cu(OTf)2, Mg(OTf)2, Zn(OTf)2, Sc(OTf)3, Eu(OTf)3, and Yb(OTf)3, it was found that Sc(OTf)3 gave higher product yield. In addition, the combination of Sc(OTf)3/ILs displayed good recyclability in this transformation. In 2014, Anbarasan and Saravanan

• nucleophilic attack of TMSN3 to deliver product 11 (Scheme 7). Tian and Chang et al. could synthesize 3‑sulfenylated coumarin compounds 13 by using N-sulfanylsuccinimides 1 under a Lewis acid catalysis system (Scheme 8) [48]. Additionally, oxidation of 3-sulfenylated coumarins utilizing (diacetoxyiodo)benzene

Cyclization of 1-aryl-4,4,4-trichlorobut-2-en-1-ones into 3-trichloromethylindan-1-ones in triflic acid

• Vladislav A. Sokolov,
• Andrei A. Golushko,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2023, 19, 1460–1470, doi:10.3762/bjoc.19.105

• -enones) undergo intramolecular transformation into 3-trichloromethylindan-1-ones (CCl3-indanones) in Brønsted superacid CF3SO3H (triflic acid, TfOH) at 80 °C within 2–10 h in yields up to 92%. Protonation of the carbonyl oxygen of the starting CCl3-enones by TfOH affords the key reactive intermediates

• ; indanones; trichloromethyl group; triflic acid; Introduction Superelectrophilic activation of organic compounds under the action of strong Brønsted and Lewis acids is an effective method for the synthesis of various carbocycles and heterocycles, and polyfunctional compounds (see books [1][2] and reviews [3

• =CHC(=O)Me] with arenes in Brønsted superacid TfOH (triflic acid, CF3SO3H) furnishes 3-methyl-1-trichloromethylindenes (Scheme 1a) [11]. Based on NMR analysis in TfOH and theoretical DFT calculations, it has been found that the reaction proceeds through an intermediate formation of the O-protonated

Functions of enzyme domains in 2-methylisoborneol biosynthesis and enzymatic synthesis of non-natural analogs

• Binbin Gu,
• Lin-Fu Liang and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1452–1459, doi:10.3762/bjoc.19.104

• diphosphate synthase (FPPS) and 2MIBS from Streptomyces coelicolor [26] (Scheme 1B). Crystal structures of both enzymes have been obtained [27][28] and allowed for a deep structure-based investigation of 2MIBS through site-directed mutagenesis [29]. The predicted amino acid sequences of 2MIBS homologs from

• alignment with the short 2MIBS from Longispora albida DSM 44784 (WP_018349754) the border between domains A and B in the 2MIBS from S. coelicolor was identified. Domain A spans the amino acid residues 1–115 and domain B includes the amino acid residues 115–440. The gene sequences for both domains were

α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping

• Angel Palillero-Cisneros,
• Paola G. Gordillo-Guerra,
• Fernando García-Alvarez,
• Olivier Jackowski,
• Franck Ferreira,
• Fabrice Chemla,
• Joel L. Terán and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2023, 19, 1443–1451, doi:10.3762/bjoc.19.103

• . Trialkylboranes can react in a similar way with enones [3] whereas, distinctively, suitable acceptors for the reaction with dialkylzinc reagents also include α,β-unsaturated carboxylic acid derivatives such as α,β-unsaturated (di)esters [4][5], N-enoyloxazolidinones [6][7], N-enoyloxazolidines [8], or

• . Trapping of this enolate would lead to β-amino acid units, a class of compounds that has attracted a great deal of attention [19][20][21][22][23][24]. An obvious possible shortcoming that had to be considered was still that the generated zinc enolate III having a β-amino group could undergo β-elimination

• . Importantly, the protocol was found to be similarly applicable with enoates 8b (Table 3, entry 6) and 8c (entry 7) having tert-butyl and benzyl ester groups, which, as the methyl ester unit, are typical in the context of amino acid synthesis. ZnBu2 was also amenable to 1,4-addition (Table 3, entry 8), but not

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• heteroleptic Cu(I) complexes combining the malonic acid-derived anionic NHC and a neutral imidazol-2-ylidene were also obtained in a very selective manner (Scheme 12). As discussed later, many of these complexes were employed as catalysts. In 2015, Collins et al. [27] compared the stability and reactivity of

• explored the application of a thiazolylidene-based Cu(I) complex as catalyst for [3 + 2] cycloaddition reactions. They prepared an ethylene-linked bisthiazol-2-ylidene dicopper(I) complex 136 which showed high catalytic activity (Scheme 53). The activity increased upon addition of acetic acid, particularly

Functional characterisation of twelve terpene synthases from actinobacteria

• Anuj K. Chhalodia,
• Houchao Xu,
• Georges B. Tabekoueng,
• Binbin Gu,
• Kizerbo A. Taizoumbe,
• Lukas Lauterbach and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1386–1398, doi:10.3762/bjoc.19.100

• synthase homologs from diverse actinobacteria that were selected based on a phylogenetic analysis of more than 4000 amino acid sequences were investigated for their products. For four enzymes with functions not previously reported from bacterial terpene synthases the products were isolated and their

• , Supporting Information File 1). The closest characterised terpene synthase with an amino acid sequence identity of 25% is the (1(10)E,4E,6S,7R)-germacradien-6-ol synthase from Streptomyces pratensis [33]. The recombinant enzyme efficiently converted FPP into one sesquiterpene alcohol whose electron

• . brevicatena (Table 1, entry 5) showed the highly conserved motifs with a modified aspartate-rich region (86DDHRN) and the NSE triad 227NDLHSMPKE (Figure S33, Supporting Information File 1). This enzyme is closely related to the epi-isozizaene synthase from S. coelicolor (EIZS) [24], but is with an amino acid