- P(III)-Mediated Cascade C-N/C-S Bond Formation: A Protocol towards the Synthesis of N,S-Heterocycles and Spiro Compounds
-
A P(III)-mediated entry towards construction of C?N/C?S bond has been devised. The developed heterocyclization method was exercised for the synthesis of a diverse range of N,S-heterocycles and related spiro molecules. P(NMe2)3 revealed the maximum efficacies under the aerobic reaction conditions and a spectrum of bis-nucleophiles, and isothiocyanates were tolerated well to serve the access of manifold immense molecules. (Figure presented.).
- Polina, Saibabu,Putta, V. P. Rama Kishore,Gujjarappa, Raghuram,Singh, Virender,Pujar, Prasad Pralhad,Malakar, Chandi C.
-
p. 431 - 445
(2020/12/07)
-
- Reagent-Controlled Divergent Synthesis of 2-Amino-1,3-Benzoxazines and 2-Amino-1,3-Benzothiazines
-
A reagent-controlled chemoselective process has been devised for the synthesis of 4H-1,3-benzoxazines and related biologically important heterocycles in high yields under mild conditions. These scaffolds could be efficiently constructed using two different chemoselective reactions that rely on the choice of reagents and reaction conditions. The treatment of various 2-amino-arylalkyl alcohols with isothiocyanates afforded thiourea intermediates, which were reacted in situ with molecular iodine in the presence of triethylamine to give 2-amino-4H-1,3-benzoxazines, whereas the corresponding 2-amino-4H-1,3-benzothiazines were obtained by the reaction of thiourea intermediates in the presence of T3P (a mild cyclodehydrating agent) and triethylamine as the base. The described protocol represents the first example for the synthesis of 4H-1,3-benzoxazines via the dehydrosulfurization method using molecular iodine as the reagent.
- Putta, V. P. Rama Kishore,Vodnala, Nagaraju,Gujjarappa, Raghuram,Tyagi, Ujjawal,Garg, Aakriti,Gupta, Sreya,Pujar, Prasad Pralhad,Malakar, Chandi C.
-
p. 380 - 396
(2020/01/22)
-
- 2-ISOTHIOCYANATOBENZYLPYRIDINIUM BROMIDE - AN INTERMEDIATE FOR THE SYNTHESIS OF 2-ARYLAMINO-4H-BENZOTHIAZINES
-
2-Bromomethylphenyl isothiocyanate reacts with pyridine to yield 2-isothiocyanatobenzylpyridinium bromide, which afforded N-aryl-N'-(2-benzylpyridinium)thiourea bromides.Deprotonization of the latter with aqueous NaOH gave N-aryl-N'-(2-benzylpyridinium) t
- Gonda, Jozef,Kristian, Pavol
-
p. 2810 - 2816
(2007/10/02)
-
- SOME NUCLEOPHILIC REACTIONS OF 2-ISOTHIOCYANATOBENZYL BROMIDE. A NEW SIMPLE SYNTHESIS OF 2-SUBSTITUTED 4H-BENZO-THIAZINES
-
N-Bromosuccinimide reacts with O-tolyl isothiocyanate to afford 2-isothiocyanatobenzyl bromide, a new type of bifunctional synthon.Nucleophiles I(1-), SCN(1-), 4-CH3C6H4SO2(1-) and hexamethylenetetramine yield substitution products of bromine.Amines and phenols react exclusively with the NCS grouping under formation of unstable thioureas, which in turn cyclize to the corresponding 4H-benzothiazines.Structure of these compounds was corroborated by IR, 1H, 13C NMR and mass spectral data and backed by elemental analysis.
- Gonda, Jozef,Kristian, Pavol
-
p. 2802 - 2809
(2007/10/02)
-