Reference

4-Hydroxy-6-methyl-2-pyrone

4-Hydroxy-6-methyl-2-pyrone. (Rohm and Haas Co., USA). Jpn. Kokai Tokkyo Koho JP 58216183 A2 15 Dec 1983 Showa, 8 pp. (Japanese). (Japan). CODEN: JKXXAF. CLASS: IC: C07D309-38. APPLICATION: JP 83-9787 24 Jan 1983. PRIORITY: US 82-384854 4 Jun 1982. DOCUMENT TYPE: Patent CA Section: 27 (Heterocyclic Compounds (One Hetero Atom)) The title pyrone (I) was prepd. by treating dehydroacetic acid (II) with 93-95 wt.% H2SO4 at 95-105° and 1 kg/cm2, during which the H2SO4-II wt. ratio was adjusted to 1.5-2.5:1. Thus, a mixt. of II 6.66 and 96.9% H2SO4 13.24 kg was heated 2.In this experiment, several chemicals are used like 520-45-6 and 675-10-5 5 h at 96-98°, cooled to 22°, H2O added, and the ppt. washed and dried to give 74% I. .

Synthesis of 6-methyl-4(1H)-pyridone-3-carboxylic acid

All Rights Reserved. Synthesis of 6-methyl-4(1H)-pyridone-3-carboxylic acid. Li, Yujuan; Wang, Dun; Yu, Xin; Xu, Shusen (General Pharmaceutical Factory, Harbin Pharmaceutical Group Co., Ltd., Harbin 150046, Peop. Rep. China).Several reagents with their cas registry numbers 4637-24-5 and 675-10-5 are used here. Shenyang Yaoke Daxue Xuebao, 22(1), 17-18 (Chinese) 2005 Shenyang Yaoke Daxue Xuebao Bianjibu. CODEN: SYDXFF. ISSN: 1006-2858. DOCUMENT TYPE: Journal CA Section: 26 (Biomolecules and Their Synthetic Analogs) Section cross-reference(s): 27 6-Methyl-4(1H)-pyridine-3-carboxylic acid, a key intermediate of cefpiramide, was prepd. from 4-hydroxy-6-methyl-2H-pyran-2-one and N,N-dimethylformamide di-Me acetal by condensation reaction and rearrangement. The product was obtained in overall yield of 39.6% higher than that reported in literature and its structure was confirmed by the m.p., 1H-NMR, and MS. Cefpiramide is a b-lactam antibiotic. .