Benzopyran

About: Benzopyran is a research topic. Over the lifetime, 1889 publications have been published within this topic receiving 15235 citations.

Structure and photochemical characteristics of 1′,3′,3′,trimethyl-4′, 5′-benzo-6-nitrospiro[indoline-2,2′-[2H-1]benzopyrant]

Abstract: 1. An x-ray crystallographic investigation of 1′,3′,3′-trimethyl-4′, 5′-benzo-6-nitrospiro[indoline-2,2′-[2H-1]benzopyran] was undertaken. 2. It was shown that the annellation of an additional benzene ring to the indoline fragment does not affect the structure of the spiropyran ring of the molecule but the Cspiro-O bond cleaved during photoexcitation is elongated and is the most weakened bond even in the ground state. 3. The different photochemical activities of the spiropyrans with identical Cspiro-O bond length in the ground state probably depend on the nature of the change in the length of this bond in the excited state.

1H-2-Benzopyran-1-yl alkyl on 1-(isochroman-1-yl)alkyl piperazines

Abstract: 1H-2-benzopyran-1-yl alkyl or 1-(isochroman-1-yl) alkyl 4-phenyl piperazines are prepared and exhibit antipsychotic and hypotensive activity.

Combined use of tandem mass spectrometry and computational chemistry to study 2H-chromenes from Piper aduncum.

Abstract: Natural 2H-chromenes were isolated from the crude extract of Piper aduncum (Piperaceae) and analyzed by electrospray ionization tandem mass spectrometry (ESI-MS/MS) applying collision-induced dissociation. Density functional theory (DFT) calculations were used to explain the preferred protonation sites of the 2H-chromenes based on thermochemical parameters, including atomic charges, proton affinity, and gas-phase basicity. After identifying the nucleophilic sites, the pathways were proposed to justify the formation of the diagnostic ions under ESI-MS/MS conditions. The calculated relative energy for each pathway was in good agreement with the energy-resolved plot obtained from ESI-MS/MS data. Moreover, the 2H-chromene underwent proton attachment on the prenyl moiety via a six-membered transition state. This behavior resulted in the formation of a diagnostic ion due to 2-methylpropene loss. These studies provide novel insights into gas-phase dissociation for natural benzopyran compounds, indicating how reactivity is correlated to the intrinsic acid-base equilibrium and structural aspects, including the substitution pattern on the aromatic moiety. Therefore, these results can be applied in the identification of benzopyran derivatives in a variety of biological samples.