3‐Oxo‐1,2‐benzoisothiazoline‐2‐acetic acid 1,1‐dioxide derivatives. II. Reaction of amides with alkoxides

Abstract

Reaction of some 3‐oxo‐1,2‐benzoisothiazoline‐2‐acetamide 1,1‐dioxides (1a‐f) with alkaline alkoxides was carried out under various conditions. Under mild conditions, 1a‐f with sodium methoxide gave o‐(N‐carbox‐amidomethylsulfamyl)benzoic acid methyl esters (2a‐f, R = CH3). Compounds 1a or 2a reacted with sodium alkoxides under drastic conditions affording only ester 5. Under the same conditions, 1b‐d or 2b‐d gave 4‐hydroxy‐2H‐1,2‐benzothiazine‐3‐carboxamide 1,1‐dioxides (3b‐d), while 1e‐f or 2e‐f afforded the acid 6 in variable amounts, together with the expected benzothiazines 3e‐f. Isolation of ethyl ether as another product in the reaction of 1e‐f with sodium ethoxide supports the suggestion that the formation of 6 involves the O‐alkyl fission on the alkyl carbon of the esters 2e‐f. An explanation of these results may be related to the acidic character of the amide hydrogen in compounds 2e‐f.

1,6- and 1,7-naphthyridines. IV. Synthesis of hydroxycarboxamide derivatives

“…On the basis of literature data, the positive ferric chloride test [15], the presence in the 1 H nmr spectra of signals attributed to the enol protons, the presence of bands in the 1640-1665 range in the ir spectra and the absence of signals over 165 ppm in the 13 C nmr spectra support the enollactam structure for compounds 1 and 2.…”

“…1 H Nmr spectra of compounds 1 and 2 showed broad signals between 11.42-8.94 ppm assigned to NH and OH hydrogens, and between 7.52-9.03 ppm those corresponding to the three pyridine hydrogen atoms. 13 C Nmr spectra showed nine signals besides those belonging to the substituents. Two of them, which appeared between 157.9 and 164.5 ppm, were assigned to carbonyl carbons Ci(i') and Ch(h').…”

“…13 C Nmr spectra showed nine signals besides those belonging to the substituents. Two of them, which appeared between 157.9 and 164.5 ppm, were assigned to carbonyl carbons Ci(i') and Ch(h').…”

“…Spectral assignments of 1 H nmr (Tables I and II) and 13 C nmr spectra (Table III) [16] were made on the basis of signal multiplicity, coupling constant values, attached proton test (APT) in certain cases, and by comparison with data of related compounds [1][2][3].…”

“…Found: C, 65.14; H, 4.47; N, 14.17.N,N-Diethyl-5H-pyrrolo[3,4-b]-pyridine-5,7-(6H)-dione-6acetamide (3b).This compound was obtained in 52% yield; mp 142 °C (2propanol); lit [14]. mp 142 °C; ir: 3095, 2997, 1783, 1728, 1659, 1593, 1471,1395 cm -1 ;13 C nmr (deuteriochloroform): δ 166.0 and 165.9 (C5 and C7), 163.9 (CONR 1 R 2 ), 155.2 (C2), 151.8 (C7a), 131.3 (C4), 127.5 (C4a), 127.3 (C3), 39.2 (CH 2 CO), 41.3 and 40.8 (CH 2 CH 3 ), 12.8 (CH 3 ); ms: m/z 261 (9.5 %) (M +. ).…”