7,8-Dihydro-8-hydroxy-2-methyl-3H,6H-[1,3]thiazino[3,2-b][1,2,4]triazine-3-one

Abstract

CTH9N302S, M.W. 199.26, space group P21/c, monoclinic, a=9.770(6), b=9.601(8), c= 11.198(8) A, fl= 125.6(4) ° (from oscillation and Weissenberg photographs), Z=4, Dx = 1.542, Dm= 1"54 (1) g cm -a (by flotation), /z=31.7 cm -1. The molecules located along the same screw axes are held together by hydrogen bonds, forming infinite chains along b. The high-temperature parameters of the oxygen atom of the hydroxyl group are probably due to rapid tautomeric changes.

Synthesis, Characterization, and Crystal Structure of a Functionalized Ruthenium(II) Polypyridyl Complex with Fused Triazinone as Ligand

“…This observation is similar to that for 7,8-dihydro-8-hdroxy-2-methyl-3H,6H-[1,3]thiazino[3,2-b]-1,2,4-triazin-3-one where the corresponding oxygen is deviated from the triazine plane by 0.08 Å. 39 The mean Ru-N bond length (2.059 Å) is a typical value for this type of Ru(II) complex (2.059-2.069 Å) 38,40,41 It is noteworthy that the bond length of N8-C31 (1.288(14) Å) is a typical double bond value 42 and is significantly shorter than that of N9-C33 (1.385(14) Å) and N9-C32 (1.35(2) Å). In fact, the bond lengths of N8-C31 and N3-C11 are nearly the same and the shortest among all the C-N bond lengths in complex 1.…”

“…Similar cases can be found in some other complexes of this type (1.9−12.3°). − The PTZO ligand is essentially planar with O1 being slightly out of the triazine plane (0.1024 Å). This observation is similar to that for 7,8-dihydro-8-hdroxy-2-methyl-3 H ,6 H -[1,3]thiazino[3,2- b ]-1,2,4-triazin-3-one where the corresponding oxygen is deviated from the triazine plane by 0.08 Å …”

“…On the other hand, the N7−C32 bond length (1.51(2) Å) is predominant in single-bond character and significantly longer than that found in 6-azauridine (1.386 Å) 43 and 6-azacytidine (1.389 Å) . It is interesting that a comparably long C−N bond length was observed in 7,8-dihydro-8-hydroxy-2-methyl-3 H ,6 H -[1, 3]thiazino[3,2- b ]-1,2,4-triazin-3-one (1.52 Å) . The relatively longer bond length of N7−C32 in the triazinone ring system could be rationalized on the basis of the very short bond lengths of N7−N8 and N8−C31.…”

“…In addition the bond length of N7-N8 (1.260(16) Å) is also a typical value of a double-bond value 42 and significantly shorter than that in many other triazinone compounds and the analogues. For instance, longer N-N bond lengths are found in 6-azauridine (1.369 Å), 43 7,8-dihydro-8-hydroxy-2-methyl-3H,6H-[1,3]thiazino[3,2-b]-1,2,4-triazin-3-one (1.32 Å), 39 and 6-azacytidine (1.356 Å). 44 On the other hand, the N7-C32 bond length (1.51-(2) Å) is predominant in single-bond character and significantly longer than that found in 6-azauridine (1.386 Å) 43 and 6-azacytidine (1.389 Å).…”

“…44 It is interesting that a comparably long C-N bond length was observed in 7,8-dihydro-8-hydroxy-2methyl-3H,6H-[1, 3]thiazino[3,2-b]-1,2,4-triazin-3-one (1.52 Å). 39 The relatively longer bond length of N7-C32 in the triazinone ring system could be rationalized on the basis of the very short bond lengths of N7-N8 and N8-C31. The O1-C32 distance of 1.265 Å shows that the keto form (H-N-Cd O) is predominant in complex 1.…”