Regioselective C(sp2)-H imidation of arenes by redox neutral visible-light photocatalysis.

We report herein a redox neutral visible light-induced regioselective C(sp2)-H imidation of electron-rich arenes and heteroarenes using conceptually designed redox-active 1 as a source of the N-centered imidyl radical. Structurally diverse aromatic imides were obtained in moderate to good yields. This methodology has been successfully employed for the late stage imidation of complex molecules and has also been applied towards the formal total synthesis of the marine natural products carpatamides A, B and D. It has further been shown that the generated imides can easily be converted to the corresponding anilines in situ directly.

Atom-Economical Palladium Carbon-Catalyzed de Novo Synthesis of Trisubstituted Nicotinonitriles.

A de novo palladium carbon-catalyzed synthesis of trisubstituted nicotinonitriles from easily synthesized homopropagylic or homoallylic aromatic alcohols in the presence of nitriles has been explored. The mechanism proceeds with an interesting generation of a Pd(II)-C palladacycle followed by an oxidative aromatization to generate the pyridine core. The pyridine core is generated with a noteworthy C-C bond cleavage in the case of the substituted nitriles. The moderate yields and easy separation of the products lend a unique importance to this one-pot methodology.

Phenyl trimethyl ammonium tribromide mediated robust one-pot synthesis of spiro-oxacycles - an economic route - stereoselective synthesis of oxaspirohexacyclodieneones.

This paper entails the first recognition of Phenyl Trimethyl Ammonium Tribromide (PTAB) as an effective reagent for spiro-cyclizations proceeding via oxidative dearomatization. The experiment exhibits economical, metal and ligand free one-pot accomplishment of these significant transformations. The described protocol presents the first generalised methodology of spiro-oxacycle synthesis which can be applied towards various directions. A stereoselective synthesis of oxa-spirocyclooxadieneones has been accomplished.

Peripheral plasma progesterone: a marker for determining cyclicity in yaks (Poephagus grunniens L.).

An attempt was made to determine cyclicity in yaks using plasma progesterone during the breeding and non-breeding seasons. Fifteen non-lactating yaks were used in this experiment. During the breeding season (July to November), blood samples were collected from 8 yaks at least twice weekly until estrus was observed and then at 2 days interval for 30 days. During the non-breeding season (February to March), blood samples were collected from the same number of yaks at 2-day interval for 30 days. Progesterone was determined in plasma samples by radioimmunoassay. During the breeding season, plasma progesterone at estrus was basal (< or = 0.2 ng/ml). Concentrations increased thereafter with a sharp increase during the late luteal phase, typically reaching peak levels around day 15. Concentrations then declined rapidly over the following 4 days, reaching basal levels at estrus. A high proportion (66.7%) of potential estrous periods (based on progesterone concentrations) went undetected, indicating that silent or weak estrus was a prominent problem in yak cows. During the non-breeding season, three animals were found to be cycling as determined by the patterns of plasma progesterone. Yet, behavioral symptoms of estrus were not observed in any of these yak cows. We conclude that peripheral plasma progesterone concentrations can be used to monitor cyclicity in yak cows effectively.