Sourav Basu

STEREOSELECTIVE SYNTHESIS OF A NEW HEXANOR(C23-C28)CASTASTERONE-20,22-ETHYL DIETHER FROM 16-DEHYDROPREGNENOLONE ACETATE AND ITS PLANT GROWTH PROMOTING ACTIVITY

Abstract Stereoselective synthesis of a new hexanor(C23–C28)castasterone-20,22-ethyl diether 22 has been achieved in sixteen steps from cheap and readily available 16-dehydropregnenolone acetate. This new brassinosteroid has shown typical brassin activity in mung bean epicotyl bioassay.

Synthesis of 11β-(4-dimethylaminophenyl)-17β-hydroxy-17α- (3-methyl-1-butynyl)-4, 9-estradien-3-one and 11β-(4-acetophenyl)- 17β-hydroxy-17α-(3-methyl-1-butynyl)-4, 9-estradien-3-one: two new analogs of mifepristone (RU-486)☆,☆☆,☆☆☆

From the structure activity relationship, two new analogs, 2 and 3, of the potent progesterone antagonist mifepristone 1 have been designed. The syntheses of these two analogs have been achieved in eleven steps through modified synthetic sequences and improved procedures starting from (+)-estrone. In comparison with mifepristone 1, the relative binding affinities of compound 2 for the progesterone receptor was found to be more, whereas that of compound 3 was less.

Vicinal dihydroxylation of alkenes with tetradecyltrimethylammonium permanganate and potassium hydroxide in a two phase solvent system

Vicinal cis-dihydroxylation of alkenes has been carried out in good yields using tetradecyltrimethylammonium permanganate in a two phase solvent system with an inorganic base present from the beginning of the reaction. With benzyltrimethylammonium hydroxide as an organic base in nonaqueous solvent system reasonably good yields of diols are realised.

Manganese-mediated novel dibromination of olefins with tetradecyltrimethylammonium permanganate and trimethylbromosilane

The synthetic utility of tetradecyltrimethylammonium permanganate–trimethylbromosilane as an excellent new reagent for the stereo- and chemo-selective trans-dibromination of alkenes is reported.

TITANIUM TETRACHLORIDE-MEDIATED CARBON-CARBON CHLOROCYANOETHYLATION OF ANISOLE : SYNTHESIS OF TYROSINE DERIVATIVES

Abstract Chlorocyanoethylation of anisole with 2-chloroacrylonitrile in presence of titanium tetrachloride furnished α-chloro-β-(4-methoxyphenyl)propionitrile. This on simple reaction sequence was converted to (±) methyl-α-amino-β-(4-methoxyphenyl)propionate, a tyrosine derivative.

Asymmetric synthesis towards doxanthrine, a dopamine D1 full agonist

Asymmetric synthesis of O-methyl doxanthrine is accomplished with high diastereo- and enantioselectivity from β-aryloxyamino acid derived from D-serine.

Abstract B43: Novel small-molecule human STING agonists generate robust Type I interferon responses in tumors

Background: A significant proportion of human cancers grow unchecked by the immune system. These cold or non-inflamed tumors do not have a T cell infiltrate and it has been shown that activation of innate immune signaling through STING (Stimulator of Interferon Genes) generates a Type I interferon (Type 1 IFN) signal that increases T cell infiltration into these tumors leading to significant regression (Woo et al., Ann Rev Immunol 2015). Activation of STING using small molecules is a novel therapeutic approach gaining significant traction in the translational immuno-oncology research community. Methods: We used a pharmacophore based approach to identify small molecule human STING agonists. Our compounds were assessed (1) in reporter gene assays on HEK293T cells containing stably transfected hSTING polymorphs, (2) by immunoblots to confirm pSTING, pTBK1, pIRF3, (3) by real-time PCR monitoring induction of Type I cytokines in human tumor cell lines, isolated human PBMCs and dendritic cells (hDC). Promising lead compounds were further evaluated for anti-tumor activity in c57/BL6 syngeneic and xenografted SCID mice humanized with hPBMC and dendritic cells from human donors. Results: We have designed and synthesized potent non-macrocyclic, non-nucleoside human STING agonists. Our lead compound CRD-100 described here has good oral bioavailability and drug like properties (Patents filed). Treatment of an isolated cell free system containing purified recombinant STING and TBK1 leads to STING phosphorylation confirming that CRD-100 is a direct STING binder. Evidence of direct binding also comes from low temperature isothermal calorimetry. CRD-100 activates all five common hSTING variants with agonist EC50 comparable to CDNs in the pIRF3 reporter assay. Treatment of hSTING transfected cells, human tumors cell lines or hPBMC with CRD-100 leads to phosphorylation of IRF3, TBK1 and STING. CRD-100 also causes the maturation of hDCs and the release of innate and adaptive inflammatory cytokines such as IFNβ and TNFα from hPBMCs. Once fortnightly doses of CRD-100 delivered intra-tumorally caused tumor regression in syngeneic and xenografted tumors. Conclusions: The ability of hSTING agonists to generate anti-tumor immune responses in cold tumors in murine models makes them a promising therapeutic option either as a single agent or in combination with existing or developing therapies. CRD-100 has conventional small molecule drug like properties making it an attractive drug candidate for advanced development as an immune mediated anti-cancer agent. Disclosure of Chemical Structures: We will not be disclosing chemical structures at AACR. Citation Format: Monali Banerjee, Sandip Middya, Sourav Basu, Ritesh Shrivastava, Rajib Ghosh, Dharmendra Yadav, Thanilsana Soram, Ritika Raina, David C. Pryde, Kavita Puniya, Navin Pandit, Rubeenaparveen R. Mansuri, Vijay Kadam, Sabyasachi Debnath, Sunny Goon, Anuj Singh, Anindita Middya, Nidhi Rawat, Arjun Surya. Novel small-molecule human STING agonists generate robust Type I interferon responses in tumors [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr B43.

Manganese-mediated Stereoselective and Chemoselective trans-Dichlorination of Alkenes with Tetradecyltrimethylammonium Permanganate–Trimethylchlorosilane

An excellent reagent for the chemo- and stereo-selective trans-dichlorination of alkenes in high yield has been formulated by mixing tetradecyltrimethylammonium permanganate, a relatively stable crystalline solid, with trimethylchlorosilane in methylene dichloride.