- Reagent-Controlled Divergent Synthesis of 2-Amino-1,3-Benzoxazines and 2-Amino-1,3-Benzothiazines
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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.
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p. 380 - 396
(2020/01/22)
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- Synthesis and biological evaluation of a new class of benzothiazines as neuroprotective agents
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Neurodegenerative diseases are disorders related to the degeneration of central neurons that gradually lead to various, severe alterations of cognitive and/or motor functions. Currently, for no such diseases does any pharmacological treatment exist able to arrest its progression. Riluzole (1) is a small molecule able to interfere with multiple cellular and molecular mechanisms of neurodegeneration, and is the only approved treatment of amyotrophic lateral sclerosis (ALS), the progression of which proved to significantly slow, thus increasing somewhat average survival. Here we report the synthesis of differently functionalized 4H-3,1-benzothiazine (5–6) and 2H-1,4-benzothiazine (7) series as superior homologues of 1. Biological evaluation demonstrated that amidine 4H-3,1-benzothiazine derivatives 5b-d can reduce glutamate and LDH release in the oxygen/glucose deprivation and reperfusion model (OGD/R) applied to brain slices with a higher potency than 1. Moreover the mentioned compounds significantly reduce glutamate- and 6-hydroxydopamine (6-OHDA)-induced cytotoxicity in neuroblastoma cells. In addition, the same compounds limit ROS formation in both neuronal preparations. Finally, 5c proved effective in inhibiting neuronal voltage-dependent Na+and Ca2+-channels, showing a profile comparable with that of 1.
- Mancini, Alessandra,Chelini, Alessia,Di Capua, Angela,Castelli, Loretta,Brogi, Simone,Paolino, Marco,Giuliani, Germano,Cappelli, Andrea,Frosini, Maria,Ricci, Lorenzo,Leonelli, Erminia,Giorgi, Gianluca,Giordani, Antonio,Magistretti, Jacopo,Anzini, Maurizio
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p. 614 - 630
(2016/12/09)
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- AMIDINE, THIOUREA AND GUANIDINE DERIVATIVES OF 2-AMINOBENZOTHIAZOLES AND AMINOBENZOTHIAZINES, NOVEL PHARMACOLOGICAL AGENTS FOR THE TREATMENT OF NEURODEGENERATIVE PATHOLOGIES
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The present invention relates to novel amidine, thiourea and guanidine derivatives of appropriately substituted 2-aminobenzothiazoles, 2-amino-3,l-4H-benzothiazines and 3- amino-l,4-3H-benzothiazines, as understood from formula (I), the related pharmaceutically acceptable salts and solvates thereof: Formula (I): and the use of said products and the corresponding pharmaceutical formulations for the treatment of neurodegenerative pathologies such as cerebral ischemia, neurodegeneration induced by cranial trauma, Alzheimer's disease, Multiple Sclerosis and Amyotrophic Lateral Sclerosis.
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Page/Page column 28
(2009/05/29)
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- SOME NUCLEOPHILIC REACTIONS OF 2-ISOTHIOCYANATOBENZYL BROMIDE. A NEW SIMPLE SYNTHESIS OF 2-SUBSTITUTED 4H-BENZO-THIAZINES
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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
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p. 2802 - 2809
(2007/10/02)
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- Synthesis of Some New N-Benzothiazinyl-N'-aryl/pyridyl-thioureas as Potential Anthelmintic Agents
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A number of new N-(4H-3,1-benzothiazin-2-yl)-N'-aryl, -N'-pyridyl- and -N'-5-substituted-pyridyl-thioureas (2-12) and N-(2H-1,4 benzothiazin-3-yl)-N'-pyridylthioureas (14-16) have been synthesized and tested for their anthelmintic activity against Nematos
- Shridhar, D. R.,Rao, K. Srinivasa,Bhopale, K. K.,Tripathi, H. N.,Sai, G. S. T.
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p. 471 - 473
(2007/10/02)
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