✦ LIBER ✦

Synthesis of the 4-methyl-1,2-oxazetidine-4-carboxylic acid moiety of the originally proposed halipeptin A and B structures

✍ Scribed by Barry B Snider; Jeremy R Duvall

Publisher: Elsevier Science
Year: 2003
Tongue: French
Weight: 309 KB
Volume: 44
Category: Article
ISSN: 0040-4039
DOI: 10.1016/s0040-4039(03)00542-2

No coin nor oath required. For personal study only.

✦ Synopsis

O-Alkylation of N-hydroxycarbamate 6 with iodo ester 5 affords 15, which was elaborated to mesylate 4. Intramolecular N-alkylation affords methyl N-Boc-4-methyl-1,2-oxazetidine-4-carboxylate (3). The geminal coupling constant of the methylene protons is 8.5 Hz, which is much smaller than the 12.0 Hz reported for halipeptins A and B. This confirms that the halipeptins do not contain an oxazetidinecarboxylic acid as originally proposed in structure 1, but a thiazoline as in the revised structure 2. The unusual O-alkylation of 5 probably proceeds by an electron transfer mechanism.

📜 SIMILAR VOLUMES

Syntheses and stereochemistry of (±)-4α-

Syntheses and stereochemistry of (±)-4α-methyl-10β-hydroxy-trans-1,2,3,4,5,6,7,10-octahydrophenanthrene-4β-carboxylic acid lactone and the four epimers of (±)-4-methyl-1,2,3,4,5,6,7,10-octahydro-phenanthrene-4-carboxylic acid.

✍ U.R. Ghatak; A.K. Banerjee; N.R. Chatterjee; J. Chakravarty 📂 Article 📅 1967 🏛 Elsevier Science 🌐 French ⚖ 388 KB

Utilization of 2-benzo[b]furan carboxyli

Utilization of 2-benzo[b]furan carboxylic acid hydrazide in the synthesis of 1,3,4-oxadiazole derivatives

✍ Yu-Xia Da; Zhi Yang; Zheng-Jun Quan; Zhang Zhang; Xi-Cun Wang 📂 Article 📅 2009 🏛 Journal of Heterocyclic Chemistry 🌐 English ⚖ 141 KB

## Abstract magnified image In this study, the synthesis of series of 2‐benzo[__b__]furan‐substituted 1,3,4‐oxadiazole derivatives using readily available 2‐benzo[__b__]furan carboxylic acid hydrazide as starting material has been investigated. J. Heterocyclic Chem., (2009).

The structures of the adducts formed fro

The structures of the adducts formed from organotin moieties and 1-[(4-methoxyphenylimino)methyl]-2-naphthol. Crystal structure of chloro-trimethyl[1-[

✍ Siang-Guan Teoh; Soon-Beng Teo; Guan-Yeow Yeap; Hoong-Kun Fun; Peter J. Smith 📂 Article 📅 1993 🏛 Elsevier Science 🌐 English ⚖ 470 KB

A Convenient Method for the Preparation

A Convenient Method for the Preparation of 4-Hydroxy-2-methyl-1-oxo-1,2-dihydroisoquinoline-3-carboxylic Acid Derivatives.

✍ Maria Mercedes Blanco; Maria Sol Shmidt; Celia Beatriz Schapira; Isabel Amalia P 📂 Article 📅 2006 🏛 John Wiley and Sons ⚖ 18 KB 👁 2 views

Synthesis of a Series of 2,3-Disubstitut

Synthesis of a Series of 2,3-Disubstituted 4H-1,4-Benzothiazines and X-Ray Crystal Structure of Ethyl 7-Chloro-3-methyl-4H-1,4-benzothiazine-2-carboxylate.

✍ Anshu Dandia; Pritima Sarawgi; Michael B. Hursthouse; Ann L. Bingham; Mark E. Li 📂 Article 📅 2006 🏛 John Wiley and Sons ⚖ 18 KB 👁 3 views

ChemInform Abstract: Total Synthesis and

ChemInform Abstract: Total Synthesis and Antifungal Activity of 9-Methoxystrobilurin L as the Originally Proposed 1,4-Benzodioxan Structure.

✍ Yasuyuki Aiba; Daiju Hasegawa; Takahiro Marunouchi; Koh Nagasawa; Hiromi Uchiro; 📂 Article 📅 2010 🏛 John Wiley and Sons ⚖ 33 KB