6302-94-9

Structural analyses of a series of 5-alkyl-[1,3,5]-dithiazinanes [R = Me (1), iPr (2), tBu (3)], their N-BH3 adducts (1BH3-3BH3) and their 2-alkyl (R0) derivatives are reported: R = Me, R0 = Me (7); R = Me, R0 iPr (8); R = iPr, R0 =Me (10); R = tBu, R0 =Me (11); and R = Me, R0 = nBu (12). The reaction of 2-lithium-5-methyl-[1,3,5]-dithiazinane (4) with I2 affords the bis-(5-methyl-[1,3,5]-dithiazinan-2-yl) (13). Isostructural compounds: [2,5,5]-trimethyl-[1,3,5]-dithiazinan-5-ium iodide (14), 5-borane-2,5-dimethyl- [1,3,5]-dithiazinane (15) and 2,5,5-trimethyl-[1,3,5,6]-dithiazaborata (16) are compared. Structures of 7, 8 and 10-13 were determined by 11B, 13C and 1H NMR and the X-ray diffraction analyses of 2, 1BH3, 13 and 14 are reported. Optimization of two chair conformers of heterocycles 1-3, 1BH3-3BH3, 7, 9 (R = Me, R0 = tBu), 13-16 were performed by HF/6-31++G and B3LYP/6-31G(d,p) methods and their minimum energy is compared. 2-Alkyl substituents or N-BH3 anchor the [1,3,5]-dithiazinane ring conformation allowing the analyses of steric and electronic interactions as well as the lone pairs effect in these molecules.

A novel procedure has been developed for selective synthesis of N-aryl-1,3,5-dithiazinanes, 1,2,6,7-tetrahydro-3,5,1,7-benzodithiadiazonine, and 6,7-dihydro-1,3,5,7-benzotrithiazonine by reactions of aniline derivatives with N-methyl-1,3,5-dithiazinane or 1,3,5-trithiane in the presence of transition and rare earth metal salts and complexes. Pleiades Publishing, Ltd., 2011.

Three-component condensations of formaldehyde with hydrogen sulfide and hydroxylamine or amino alcohols at a ratio of 3:2:1 give 47-73% of N-hydroxy(or hydroxyalkyl)-1,3,5-dithiazinanes. The reactions of CH2O with H 2S and hydroxylamine or α-amino alcohols at a ratio of 4:3:1 involve both amino and hydroxy groups, leading to the corresponding dithiazinanes. 4-Aminobutan-1-ol reacts with CH2O and H2S under analogous conditions only at the amino group to form 4-(1,3,5-dithiazinan- 5-yl)butan-1-ol.

An efficient synthesis of N-substituted dihydro-4H-1,3,5-dithiazines is described. N,N-Bis(benzotriazolylmethyl)alkylamines 1 smoothly under go cyclisation reaction in the presence of formaldehyde and hydrogen sulfide to give 5-substituted dihydro-4H-1,3,5-dithiazines 2.

New 1,3,5-heterocyclohexanes: 5-alkyl-1,3,5-dioxazines (R= iPr, tBu and [R]-α-methylbenzyl), 3,5-di([R]-α-methylbenzyl)-1,3,5-oxadiazine, 3,5- di([R]-α-methylbenzyl)-1,3,5-thiadiazine, 5-isopropyl-1,3,5-oxathiazine, 1- isopropyl-3,5-dimethyl-1,3,5-triazine, 1-tert-butyl-3,5-dimethyl-1,3,5- triazine are reported. Amination and transamination reactions of 1,3,5- heterocyclohexanes were investigated. Equilibria between different heterocycles were found. 13C NMR studies allowed to observe new 1,3,5- heterocycles: 1,3,5-triazines bearing two different alkyl substituents, 3,5- ditert-butyl-1,3,5-thiadiazine, 3-tert-butyl-5-isopropyl-1,3,5-oxadiazine. 1,3,5-heterocyclohexanes present a ring fluxional behavior, the ring inversion energy was calculated for dioxazines, oxadiazine, thiadiazines and triazines.

Syntheses of the dimers of axial 5-methyl-2-dithiazinyllithium (4) and equatorial 5-methyl-2-dithiazinyllithium-5-borane (5), and lithium 5-methyl-2-dithiazinanylborate-5-borane (6) are reported. Compounds 4, 5, and 6 are configurationally and conformationally stable. The 1H-, 13C-, 11B-, and 7Li-NMR study of the reactions of 4 and 5 with BH3-S(CH3)2, BH3-THF, and CH3I is presented. VCH Verlagsgesellschaft mbH,.

5-Methyl- and 5-tert-butyl-1,3,5-dithiazinane (1 and 7) react with BH3*THF, BD3*THF, and Et2O*BF3 to yield the N-coordinated adducts 2-4 (with BH3, BD3, and BF3, respectively).The conformations and spectroscopic properties of the adducts are discussed.The reactions of 1 and 7 with BY3*THF lead to the six-membered boron heterocycles 5,5-dimethyl-1,3-dithia-5-azonia-4-boratacyclohexane (5), 4,4-dideuterio-5-methyl-5-methyl-1,3-dithia-5-azonia-4-boratacyclohexane (6), and 5-tert-butyl-5-methyl-1,3-dithia-5-azonia-4-boratacyclohexane (8).Compounds 2 and 5 are isolobal isomers.The reaction of BH3 or BD3 with 7 affords, after heating, tert-butyldimethylamine-borane (9) and tert-butyldi(methyl)amine-trideuterioborane (11), respectively.The dithiazinane derivatives may be used in organic synthesis for the dimethylation of primary amines and the preparation of alkyldimethylamines with monodeuterated methyl groups. Key Words: Dithiazinanes / Dithiazoniaboratacyclohexane / Amines: dimethylation and monodeuteriomethylation

The conformational analysis of several 2-substituted 5-methyl-5-aza-1,3-dithiacyclohexanes made the evaluation of S-C-Y anomeric interactions possible, where Y = SCH3, SC6H5, COC6H5, CO2CH2CH3, and CO2C6H5.The relative order of the effects as a function of substituent is similar to that previously encountered in the corresponding 2-substituted 1,3-dithianes; however, the effects are smaller in magnitude in the title compounds, and we attribute this to the decreased ring dipole, which leads to a diminished influence of dipole-dipole interactions on these equilibria.Nevertheless, the observed anomeric effects are significant and can be explained in terms of endo and exo hyperconjugative interactions, which indicate that second-row elements are able to perticipate in anomeric interactions.Plots of ln K versus 1/T are linear, permiting evaluation of the enthalpic and entropic contributions to the S-C-Y anomeric effect.For the S-C-S segment, the effect is of enthalpic origin and overcomes unfavorable steric and entropic components in the axial conformer.For the compounds incorporating S-C-C(O) segments, the entropy term is mainly responsible for the axial predominance; the measured ΔH0 ca. 0 for these derivatives still reflects a significant enthalpic anomeric effect owing to the countervailing steric effects in the axial conformers.

-