Design and Synthesis of (E)-4-(2-Phenyl-2H-chromen-3-yl)but-3-en-2-ones and Evaluation of their In Vitro Antimicrobial Activity

Letters in Organic Chemistry, 2015, 12, 1-7

Design and  Synthesis  of  (E)-4-(2-Phenyl-2H-chromen-3-yl)but-3-en-2-ones and Evaluation of their In Vitro Antimicrobial Activity

Sabita Nayak1,*, Subhendu Chakroborty1, Sujitlal Bhakta1, Pravati Panda1, Seetaram Mohapatra1, Sanjeet Kumar2, Padan Kumar Jena2 and Chandrasekhar Purohit3

1Department of Chemistry and 2Department of Botany, Ravenshaw University, Cuttack, Odisha, India; 3National Insti- tute of Science Education and Research, Bhubaneswar, Odisha, India

Received January 23, 2015: Revised March 10, 2015: Accepted March 25, 2015

Abstract: 2H-Chromene and its derivatives are an important class of organic compounds due to their wide range of bio- logical activities such as antimicrobial, antiviral, antiimflamatory and antitubercular agents. In the present work we have synthesized ten new 2H-chromene derivatives [(E)-4-(2-phenyl-2H-chromen-3-yl)but-3-en-2-one and its substituted ana- logues] following aldol condensation of 2H-chromene-3-carbaldehydes with acetone. These products have been character-ized by means of spectral data (1H, 13C, IR, Mass). The structure of one new compound (E)-4-(6,8-dichloro-2-phenyl-2H- chromen-3-yl)but-3-en-2-one was confirmed by X-ray analysis and the product was subsequently subjected to the in vitro evaluation of antimicrobial activity against two Gram positive bacteria Streptococcus mutans (MTCC 497) and Strepto- coccus pyogenes (MTCC 1926) and three Gram negative bacteria Vibrio cholera (MTCC 3909), Shigella flexneri (MTCC 1457) and Salmonella enteric typhi (MTCC 1252). The obtained results from in vitro antimicrobial assays by broth dilu- tion method indicated that many compounds under study exhibited excellent activity against all the microorganisms in comparison to standard kanamycin.

Grey Wagtail (Motacilla cinerea): a avifauna play an vital role to maintain the ecology

The grey wagtail (Motacilla cinerea) is a small member of the wagtail family, Motacillidae. The species looks similar to the yellow wagtail but has the yellow on its underside restricted to the throat and vent. Breeding males have a black throat. The species is widely distributed, with several populations breeding in Europe and Asia and migrating to tropical regions in Asia and Africa. They are usually seen on open marshy ground or meadows where they walk solitarily or in pairs along the ground, capturing insects that are disturbed. Like other wagtails, they frequently wag their tail and fly low with undulations and they have a sharp call that is often given in flight. This species was first described by  Marmaduke Tunstall in his 1771 Ornithologia Britannica This slim wagtail has a narrow white supercilium and a broken eye ring. The upperparts are grey and the yellow vent contrasting with whitish underparts makes it distinctive. The breeding male has a black throat that is edged by whitish moustachial stripes. They forage singly or in pairs on meadows or on shallow water marshes. They also use rocks in water and will often perch on trees. They have a clear sharp call note and the song consists of trills.  The bird is widely distributed across the Palearctic region with several well marked populations. The nominate form (includes caspica of Iran, Turkey and the Caucasus) is from western Europe including the British Isles, Scandinavia and Mediterranean region. Race melanope, which is not well separated from the nominate subspecies, is described as the population breeding in eastern Europe and central Asia mainly along the mountain chains of the Urals, Tien Shan and along the Himalayas. They winter in Africa and Asia. Race robusta breeds along the Northeastern parts of Asia in Siberia extending to Korea and Japan. They sometimes occur on the islands to the West of Alaska but have been known to occur further south in California as a vagrant.  The nest is placed near fast running streams or rivers on an embankment between stones and roots. The male in display, makes short flights up into the air and descends slowly with fluttering flight accompanied by a rapid series of chipping high notes. In Europe the nests are often made in holes in manmade structures. The clutch consists of 3–6 speckled eggs and multiple broods may be raised with declining numbers in the clutch in subsequent broods. The usual clutch size is five in Ireland and the breeding success is about 80% with predation of eggs or chicks being the main cause of breeding failure. The Canary Islands population typically have smaller clutches and the breeding season is not as short and well marked as in populations at higher latitudes. 

The incubation period is about two weeks with chicks fledging within a fortnight. They live for a maximum of 8 years in the wild.  These birds feed on a variety of aquatic invertebrates including adult flies, mayflies, beetles, crustacea and molluscs. They often forage along roadsides in winter, flushing with a sharp chi-cheep call and flying up further along the road but after some distance turning back to return to the original location. In winter, they roost in small groups. Wintering birds have been known to return to the same sites, sometimes a small urban garden, each year.