NOPR Collection:

Synthesis of 1,3,4-oxadiazole and imidazo[1,2-a]pyridine based molecular hybrids and their in vitro antituberculosis and cytotoxicity studies

2019-09-12T10:47:28Z

Title: Synthesis of 1,3,4-oxadiazole and imidazo[1,2-a]pyridine based molecular hybrids and their in vitro antituberculosis and cytotoxicity studies Authors: Maurya, Shiv Shyam; Gosain, Tannu Priya; Kidwai, Saqib; Singh, Ramandeep; Rawat, Diwan S Abstract: A library of novel 1,3,4-oxadiazole substituted imidazo[1,2-a]pyridine based molecular hybrids have been synthesized and evaluated against Mycobacterium tuberculosis H37Rv. Out of 59 compounds synthesized, ten compounds show activity in the range of 3.125-12.5 μM. Compound 8p is found to be most active with MIC₉₉ value of 3.125-6.25 μM. Further, these ten compounds have also been tested for their toxicity against THP-1 cell line and are found to be non-toxic with TC₅₀ value in the range of (10 - >50 μM) concentration. Page(s): 1005-1018

Proline catalyzed sequential α-amination/ Prins/ Ritter amidation of aldehydes: new method of construction of tetrahydropyran units

2019-09-12T10:41:31Z

Title: Proline catalyzed sequential α-amination/ Prins/ Ritter amidation of aldehydes: new method of construction of tetrahydropyran units Authors: Ahuja, Brijbhushan; Gadakh, Sunita; Sudalai, Arumugam Abstract: An efficient “one-pot” synthetic method toward highly substituted tetrahydrofuran (THP) units is reported. The key transformation involves an atom-efficient sequential proline catalyzed α-amination of aldehydes to give α-aminated aldehydes in situ and the subsequent cyclomerization with homoallylic alcohols under Prins/Ritter conditions. Notably, this method provides access to enantiopure 1,2-syn and 1,4-anti diamino alcohols via reductive ring opening of THP units. Page(s): 1019-1028

A concise formal synthesis of (-)-(6R,11R,14R)-colletallol via D-proline catalysed α-aminooxylation-Wittig olefination strategy

2019-09-12T10:38:41Z

Title: A concise formal synthesis of (-)-(6R,11R,14R)-colletallol via D-proline catalysed α-aminooxylation-Wittig olefination strategy Authors: Dey, Soumen; Gadakh, Sunita; Sudalai, Arumugam Abstract: An efficient enantioselective formal synthesis of marine macrolide (−)-(6R,11R,14R)-colletallol has been achieved starting from commercially available raw materials. The key reactions include the d-proline catalyzed α-aminooxylation of aldehyde followed by Horner-Wardsworth-Emmons olefination in a sequential fashion to give the macrolide key intermediate 5 in high enantiomeric purity (97% ee) and high overall yield (32%). Page(s): 1029-1036

Synthesis of dihydro-1,4-thiazine from α-keto spiro-thiazolidine

2019-09-12T10:33:52Z

Title: Synthesis of dihydro-1,4-thiazine from α-keto spiro-thiazolidine Authors: Utsukihara, Takamitsu; Matsushita, Masatoshi; Miyamoto, Eri; Murakami, Hikaru; Horiuchi, C Akira Abstract: The reaction of α-bromocycloalkanone with 2-aminoethanthiol leads to the regioselective formation of spirothiazolidin-2-one with the oxo-group migrating to the original position occupied by the halogen atom. The reaction of 1-thia-4-azaspiro[4.5]alkan-6-one with bromine, iodine, copper (II) salts, acid or base gives dihydro-1,4-thiazine derivatives in moderate yields. Moreover, the treatment of the spiro-thiazolidine derivatives on silica gel under microwave gives the 1,4-thiazine compound. Page(s): 1037-1041