L,3,5-Thiadiazine-2-thiones

Sulfur-nitrogen compounds 3,5-Dimethyltetrahydro-l,3,5-thiadiazine-2-thione... 

Thiomorpholinones have been prepared on cross-linked polystyrene by intramolecular thioether formation and by the lactamization of suitable amino acids (Entries 8 and 9, Table 15.34). l,3,5-Thiadiazine-2-thiones (Entry 11, Table 15.34) are not stable towards TFA/DCM (1 1) and have therefore been prepared on Sasrin cleavage from the support could be achieved using 3% TFA in DCM [411],... 

TETRAHYDRO-3,5-DIMETHYL-4H,l,3,5-OXADIAZINE-4-THIONE see TCQ275 TETRAHYDRO-2H-3,5-DIMETHYL-l,3,5-THIADIAZINE-2-THIONE see DSB200 TETRAHYDRO-3,5-DIMETHYL-2H-l,3,5-THIADIAZINE-2-THIONE see DSB200 TETRAHYDRO-p-DIOXIN see DVQOOO TETRAHYDRO-l,4-DIOXIN see DVQOOO TETRAHYDRO-2,5-DIOXOFURAN see SNCOOO... 

The full spectral characteristics including 5( H) and 5( C) chemical shifts and proton-proton couplings have been reported by Molero et for a series of derivatives of 3,5-disubstituted tetrahydro-2if-l,3,5-thiadiazine-2-thione, by Sonnenburg et for a series of bis-(2-chloroethyl)amino-... 

Carbothialdine" i.e. 4,6-dimethylperhydro-l,3,5-thiadiazine-2-thione, the reaction product of acetaldehyde with ammonia and carbon disulfide, has been known a long time (260, 288). Various structures have been proposed for it (83, 143, 164, 234). It was also known that this product may be obtained from acetaldehyde and ammonium dithiocarbamate and that two moles of aldehyde are necessary for the reaction. The reaction products of other aldehydes and amines had also been investigated with a view to elucidating their structure (31, 108). However, Ainley and co-workers (1) in 1944 were the first to determine the structure with certainty. The instability of "carbothialdines made it difficult to determine their structure by chemical means. It was by comparison of its U.V. spectrum with that of similar compounds such as (CCII) that the formula of perhydro-l,3,5-thiadiazine-2-thione (CCIV) was established, which accounts quite well for its properties. It is accepted... 

The 2//-l,3,5-thiadiazine-2-thione 8 (1.66 mmol) in Me2S04 (4mL) was heated at 90°C for 2h and then allowed to stand at rt for 24 h. After addition of 70% aq HCIO, (0.8 mL), the mixture was treated with Et20 and the precipitated product separated by suction filtration. 

Of the derivatives, 5-carboxymethyl-3-methyl-tetrahydro-l,3,5-thiadiazine-2-thione (thiadiazinethion, 17), its sodium salt, and 3,3 -ethylene-bistetrahydro-4,6-dimethyl-2H-l,3,5-thiadiazine-2-thione (milneb, 18) have been used in agriculture, the latter being effective also against apple scab, tobacco peronospora and potato blight. 

In contrast to the perhydro-3,5-dialkyl-1,3,5-thiadiazines, for which ring-inversion barriers of 9-12 kcal mol have been determined from low temperature PMR spectroscopy studies <72JCS(P2)674>, perhydro-3,5-dialkyl-l,3,5-thiadiazine-2-thiones (15) fail to show any line broadening of the proton signals even at 195 K <85ACH7>. From these results, the authors conclude that ring conversion for the thiones about carbons C-4 and C-6 is fast, with a barrier to inversion of <9 kcal mol . ... 

The products of nucleophilic attack on 4-alkoxy-6-amino-l,3,5-thiadiazine-2-thiones (81) depend on the nature of the attacking nucleophile. Primary amines bring about amino-dealkoxylation, whereas on hydrolysis, initial attack at C-4 is accompanied by ring opening to give an 7V-(alkoxy-carbonyl)thiourea. In contrast, in the presence of ethanolic sodium hydroxide an ANRORC process (Dimroth-type rearrangement) takes place to yield 6-ethoxy-l,3,5-triazine-2,4(177,37/)-dithione (82) <92NKK1450>. ... 

Analogous ring transformations have also been reported with 4,6-diamino-l,3,5-thiadiazine-2-thione hydroiodides (83) which in boiling water or with amines (R NHj) at room temperature yield... 

Methylation of 4,6-diamino-1,3,5-thiadiazine-2-thiones (102 X = NR2) with methyl iodide in boiling acetone affords the 2-methylthio-l,3,5-thiadiazinium iodides (104) in variable yields (45-81%) <71JHC1087, 88JPR241>. 2,4-Diamino-l,3,5-thiadiazine-2-thione hydriodide (83 Section... 

In contrast to the l,3,5-thiadiazine-2-thiones noted in Section 6.18.6.2, 6-chloro-2-thioxo-1,3,5-thiadiazin-4(3/0 One (21) with ethanol in cold THE undergoes ethoxy-dechlorination rather than a ring opening or ring transformation <82CB3587>. 

A(-(Benzimidoyl)imines (191 R = 2,4,6-Me3QH2) undergo cycloaddition with CS2 to yield 3,6-dihydro-6,6-bis(trifluoromethyl)-2/f-l,3,5-thiadiazine-2-thiones (192). Addition to phenyl isothiocyanate, however, is nonregioselective and produces a mixture of the 6-phenylimino-2/f-1,3,5-thiadiazine (193 51%) and the isomeric 3,6-dihydro-2/f-l,3,5-triazine-2(l//)-thione (194 28%) (Scheme 29) <84ZN(B)1442>. 

Disubstituted perhydro-l,3,5-thiadiazine-2-thiones (225) are prepared by sequential condensation of an alkylamine (RCH2NH2) with carbon disulfide, methanol, and an a-amino-acid... 

Hypolipemic activity has been noted for the 3,5-dibenzylperhydro-l,3,5-thiadiazine-2-thiones (249 R = CH2Ph) <85JAP(K)60156616, 87JAP(K)6236319>, while 4,6-diaryl-3,5-dimethyl-5,6-dihydro-4/f-l,3,5-thiadiazine-2(3//)-thiones are reported to be antiatherosclerotic agents <85EUP135109, 86EUP183173, 87JAP(K)62195377>. 

---