S,N-heterocyclics

S,N-heterocyclics 23, 592 2-pyridone ring 26, 919 quinolines, 3-hydroxy- 26, 939 thiophene ring 26,919... 

Condensation of hydrazine with formaldehyde (37% solution) and hydrogen sulfide in water in the presence of a sodium butoxide-butanol buffer (pH 10.75-11.5) gives a mixture of products. The reactant ratio is an important factor in determining the product ratio and, when a 6 4 1 ratio of HCHO-H2S-H2NNH2 was used, the perhydro-A-(l,3-thiazet-3-yl)-l,3,5-dithiazine 48 was isolated in 5-6% yield in addition to other S,N-heterocycles (Equation 18) <2006RJ0145>. 

Under snitably controlled conditions, thermal decomposition may be used to prepare certain S N componnds. For example, S2N2 is obtained by the mild thermolysis of a variety of S-N heterocycles (see Section 5.1.3) and heating solntions of SbN3 salts in boiling acetonitrile prodnces the acyclic SSNSS anion (see Section 5.3.4). Bond enthalpies for S-N componnds can be estimated from S-N bond lengths. ... 

Althongh the S3N2+ radical cation (13) has been well characterized in solntion by its characteristic five-line (1 2 3 2 1) ESR signal (g = 2.01 an = 3.15G), this S-N heterocycle is nsnally fonnd in the solid state as the dimeric cation SeN4 + (7), in which two Vtt-electron S3N2+ rings are associated via weak intermolecnlar S-S interactions [d(S-S) = 300-310pm],... 

Ring-chain tautomerism of six-membered N-unsubstituted 1,3-X, A-heterocycles (X = O, S, NR) 03EJ03025. 

Nitrile sulfides (R—C=N- S) have recently become available as reactive intermediates in the thermolysis of 5-substituted l,3,4-oxathiazol-2-ones (345) they may be trapped in 1,3-dipolar cycloadditions, resulting in S,N-heterocyclics. 

A suspension of 2 - [1 - (2 - amino - 5 - chlorophenyl) -1 - phenylmethylamino] acetic acid in xylene refluxed with stirring under a Dean-Stark head until after 6 hrs. no more water separates 7-chloro-l,3,4,5-tetrahydro-5-phenyl-2H-l,4-benzo-diazepin-2-one (startg. m. f. 372). Y 81%. R. I. Fryer et al., J. Org. Ghem. 30, 1308 (1965) S,N-heterocyclics s. M. Uskokovi6 et al., J. Org. Ghem. 30, 3111. 

Type G Syntheses [C—N—S + C—N]. Nitrile sulphides R—C N->S have recently become available as reactive intermediates in the thermolysis (at ca. 190 °C) of 5-substituted l,3,4-oxathiazol-2-ones they may be trapped by 1,3-dipolar cycloadditions, e.g. with acetylenes, resulting in S,N-heterocycles. Cycloaddition of nitrile sulphides R CNS to nitriles R CN provides a new general synthesis of 3,5-disubstituted 1,2,4-thiadiazoles (62). Yields are moderate, but are satisfactory when electrophilic nitriles are used in conjunction with aromatic nitrile sulphides. Minor amounts of (63) are formed as by-products. 

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