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Dithiazolidines

Dithiazolidines S,S-dioxides as herbicides, 6, 944 as plant growth regulators, 6, 944 rearrangements, 6, 501-504... [Pg.613]

Thiurets — see 1,2,4-Dithiazolidines, diimino-Thonzylamine antihistamine, 3, 153 Thorpe reaction benzothiophenes from, 4, 876 Thorpe-Ziegler cyclization, 2, 74 Three-membered heterocyclic compounds basicity, 7, 23... [Pg.896]

A number of ring systems have been converted into 1,2,4-thiadiazole derivatives. The most common include 5-imino-1,2,4-dithiazolidines, isoxazoles, oxadiazoles, and 5-imino-l,2,3,4-thiatriazolines. In general, a ring-opening reaction is followed by rotation and ring closure, or the heterocyclic ring may act as a masked 1,3-dipole which reacts with a suitable dipolarophile. [Pg.506]

In the 1,2,4-dithiazolidine series, 4-phenyl-3-aroylimino-5-methylimino-1,2,4-dithiazolidine (15) rearranges under the influence of benzoyl isothiocyanate into the 3-aroylimino-4-methyl-5-phenylimino-l,2,4-dithiazolidine (16) (78JOC4951). The Dimroth rearrangement is suggested to occur via a betaine as intermediate (Scheme IV.IO). It is of interest to mention that the isomerization of 15 into 16 was not observed with the Lewis acids aluminum trichloride or benzoyl chloride. [Pg.161]

A somewhat similar isomerization was observed with the sultam 5-methylimino-4-phenyl-l,3,4-dithiazolidine 1-dioxide (17 i = H). On heating at 60°C in the presence of benzoyl chloride, rearrangement into the isomeric 5-phenylimino-4-methyl-l,3,4-dithiazolidine 1-dioxide (19, 1 = H) was found (Scheme IV.ll). As intermediate can be proposed the amidinium salt 18 (78JOC4951). Furthermore, NMR-controlled test tube experiments revealed that this rearrangement also occurs under influence of aluminum trichloride and methanesulfonyl chloride. Also, the 2-phenyl derivative 17 (R = CeHs) could be isomerized it required heating in acetone with m-dichlorobenzoic acid as catalyst (Scheme IV.ll). [Pg.161]

The reaction was apparently initiated by N-sulfenylation and the possible intermediate formation of 1,2,3-dithiazolidine 193 followed by the addition of the second diamide molecule with the formation of disulfide 194 and a final rearrangement to tetrathiane 192. [Pg.211]

The sulfur atoms in certain 1,2,4-dithiazolidines can be replaced by hydroxylamine to give 1,2,4-oxadiazoles <80PHA48>. [Pg.213]

In 1991 L abbe reported that the 1,2,4-thiadiazolidine (71) and the 1,2,4-dithiazolidine (72) are interconvertible in the presence of electrophilic nitriles and give the 1,2,4-thiadiazoline-5-ones (73) as products (Scheme 18) <9UOC3268>. It is suggested that the reaction goes by a consecutive... [Pg.319]

The treatment of thiurets (diimino-l,2,4-dithiazolidines, (297)) with aromatic amines results in ring opening to form thiocarbamylguanidines (298) and sulfur cyclization to 3,5-diamino-1,2,4-thiadiazole derivatives (299) can occur spontaneously or upon oxidation (Scheme 67) <84CHEC-1(6)463 >. [Pg.346]

A similar transformation occurs when 5-imino-3-oxo-l,2,4-dithiazolidine (300) is treated with neat benzylamine to give 2-benzyl-3-oxo-5-imino-l,2,4-thiadiazolidine (301). When the reaction is carried out in ethanolic solution the thiobiuret (302) is formed which can then be oxidized to (301) (Scheme 68) <82JIC71>. [Pg.346]

A related cycloaddition/elimination reaction occurs when 5-imino-1,2,4-dithiazolidin-3-ones (300) or -3-thiones (306) are treated with phenylisocyanate to afford 2-phenyl-5-imino-1,2,4-thia-diazolidin-3-ones (307) (Equation (45)) <92JPR685>. [Pg.347]

Chiral substituted 1,2,3-dithiazolidine (48) converts slowly at RT into its stereoisomer (49) by S=0 group inversion which relieves the steric interaction with both methyl and phenyl groups (Equation (2)). The freshly prepared mixture (48) (49) = 4.4 1 (Section 4.11.8.3), when kept at 0°C in the presence of Et4N+Cl , exhibits a change of the equilibrium to 9 1 in 24 h and to 34 1 in the next 24 h, further progress being hampered by slow decomposition of (49) <91TL5885>. [Pg.416]

Tetrafluoroethane-l,2-disulfenyl dichloride (83) reacts readily with At,iV-bis(trimethylsilyl)amines to give A -substituted tetrafluoro-l,3,2-dithiazolidines (84) (Scheme 16) <85CB281l>. The same type of products are obtained by reaction with a combination of trimethylsilyl azide and alkylarenes <89CB1071>. At a low temperature (83) was reported to be cyclized by NHj to 4,4,5,5-tetrafluoro-1,3,2-dithiazolidine <93JPC9625>. [Pg.449]

Perfluoro-l,3,2-dithiazolidine 1,1,3,3-tetraoxide (73) is a useful fluorinating agent <87JAP8726264). Compound (72) (free or in salt form) is proposed for use as a polymerization catalyst <82EUP57327>, the salts are suggested as ingredients in battery electrolytes <88FRP2606217>. A- ec-Alkyl substituted... [Pg.452]

Enthalpies of formation and bond lengths (SS, SN) were calculated by the MNDO method for l,6-dihetera-6aA -thia-3,4-diazapentalenes (1), (2), and (3) as the most probable pentalene structures formed in the reaction of 3-imino-l, 2,4-dithiazolidine-5-ones with isothiocyanates (see Section 4.13.6.1.4 and Tables 1 and 2) <83JCR(S)128>. The AH data show the ring strain to be maximal for a system with an N-S-N chain (3), the most favorable being the system (1). The effect of substituents R and can be seen in both Tables 1 and 2. The same authors calculated AHf for (4), (5), and (6) to obtain values —57.4, 30.5, and 127.8 kJ mol respectively. [Pg.455]

Isomerization of 5-imino-l,2,4-dithiazolidine-3-thiones (34) into l,2,4-thiadiazolidine-3,5-di-thiones (51) by a Dimroth rearrangement (see Section 4.13.6.1.1) is a reversible process <91JPR107>. The equilibrium position strongly depends on the nature of substituents. When R = R = Me or Pr the equilibrium position is (34) (51) =1 2, with R = R = Et the ratio is 1 9. When R = Ar, R = Aik, the equilibrium is almost wholly shifted to the right. The forward process is usually accelerated by bases, the reverse by acids. When both substituents are Ar no isomerization occurs <91JPR107>. Isomerization of the 3,5-diimino analogue (52) to a monothione isomer (53), accelerated by pyridine, reaches an equilibrium ratio of (52) (53) =1 9 <89BSB879>. [Pg.461]

Dithiazolidines containing o-quinonemethide structural units in the 3,5-positions (e.g. (99)) are converted by reagents with an activated CHj group into a range of condensed heterocyclic compounds not easily accessible otherwise (Scheme 14) <85S535,86PHA283>. [Pg.469]


See other pages where Dithiazolidines is mentioned: [Pg.19]    [Pg.19]    [Pg.613]    [Pg.613]    [Pg.613]    [Pg.613]    [Pg.488]    [Pg.506]    [Pg.117]    [Pg.213]    [Pg.12]    [Pg.12]    [Pg.12]    [Pg.115]    [Pg.161]    [Pg.117]    [Pg.118]    [Pg.119]    [Pg.308]    [Pg.345]    [Pg.346]    [Pg.435]    [Pg.440]    [Pg.441]    [Pg.451]    [Pg.467]    [Pg.467]    [Pg.469]   
See also in sourсe #XX -- [ Pg.153 ]




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1,3,2-Dithiazolidine cations

1.2.4- Dithiazolidine

1.2.4- Dithiazolidine

1.2.4- Dithiazolidine-, 3- thione

5- Imino-l,2,4-dithiazolidine-3-thiones

Dithiazolidine-3,5-dione

Protection 1.2.4 dithiazolidine 3,5 dione

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