An Ir(III)-catalyzed [3 + 2] annulation of weakly coordinating N-sulfonyl ketimines with challenging α, βunsaturated nitro olefins has been achieved via redox-neutral C−H functionalization in the presence of a catalytic amount of silver hexafluoroantimonate. The generation of three consecutive stereogenic centers in a single step via direct C−H functionalization is the prime feature of this methodology. A wide array of pharmaceutically relevant nitro-substituted spirocyclic benzosultams was synthesized with good to excellent diastereoselectivity as well as in high yield starting from easily accessible substrates.

A straightforward strategy for direct incorporation of sulfonyl units into xanthene moiety for accessing xanthen-9-sulfone derivatives in good to excellent yields has been established via metal-free radical-radical cross-coupling reaction of...

A Rh­(III)-catalyzed [3 + 2] annulation of benzoxazines with nitroolefins that proceeds via redox-neutral C–H functionalization has been demonstrated, leading to the novel class of spirocycles in a single step. The construction of three continuous stereogenic centers has been achieved starting from easily accessible achiral substrates in an atom-efficient manner under mild reaction conditions. A broad range of pharmaceutically relevant nitro substituted spirocyclic 2,3-dihydro-1,4-benzoxazine derivatives has been synthesized in good to excellent yields with high diastereoselectivity.

Human papillomavirus (HPV) has been recently associated with squamous cell carcinoma of upper aerodigestive tract (SCC of UADT), but its possible role in promoting aberrant methylation in these tumors has largely remained unexplored. Herein, we investigated the association of HPV with aberrant methylation in tumor-related genes/loci consisting of the classical CpG Island Methylator Phenotype (CIMP) panel markers (p16, MLH1, MINT1, MINT2, and MINT31) and other frequently methylated cancer-related genes (DAPK1, GSTP1, BRCA1, ECAD, and RASSF1) and survival of UDAT cancers. The study includes 219 SCC of UADT patients from different hospitals of Northeast India. Detection of HPV and aberrant promoter methylation was performed by PCR and Methylation Specific PCR respectively. Association study was conducted by Logistic regression analysis and overall survival analysis was done by Kaplan-Meier plot. HPV was detected in 37% of cases, with HPV-18 as the major high-risk sub-type. Although HPV presence did not seem to affect survival in overall UADT cancers, but was associated with a favourable prognosis in head and neck squamous cell carcinoma. Hierarchical clustering revealed three distinct clusters with different methylation profile and HPV presence. Among these, the CIMP-high subgroup exhibited the highest HPV positive cases (66%). Furthermore, multivariate analysis revealed a strong synergistic association of HPV and tobacco towards modulating promoter hypermethylation in UADT cancer (OR = 27.50 [95% CI = 11.51-88.03] for CIMP-high vs. CIMP-low). The present study proposes a potential role of HPV in impelling aberrant methylation in specific tumor related loci, which might contribute in the initiation and progression of SCC of UADT.

A cobalt-catalyzed sp 2 CÀH acetoxylation of amides having 8-aminoquinoline as a directing group has been achieved using manganese (III) acetate both as an oxidant and an acetoxy source. Operational simplicity, broad range of functional group tolerance, use of an earth abundant first row transition metal, and, most importantly, exploitation of an unprecedented acetoxy source are the key features. The method is scalable and does not require any additive. The mechanism of the reaction has been established by conducting a series of experiments.