scispace - formally typeset
Search or ask a question
Topic

Benzopyran

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


Papers
More filters
Patent
21 Dec 1992
TL;DR: In this paper, reversible photochromic spiro(indoline) naphthoxazine compounds of improved photocolorability were graphically represented by the formula, ##STR1##.
Abstract: Described are novel reversible photochromic spiro(indoline) naphthoxazine compounds of improved photocolorability that may be graphically represented by the formula, ##STR1## In preferred embodiments, R1 is allyl, alkoxyalkyl, and alkyl; each R2 is alkyl or alkoxy; R3 and R4 are alkyl; R5 is alkoxycarbonyl; and R6 is hydroxy, alkoxy, or carboxy, eg, acetoxy Also described are organic host materials that contain or that are coated with such compounds Articles such as ophthalmic lenses or other plastic transparencies that incorporate the naphthoxazine compounds or combination thereof with complementary photochromic compounds, eg, naphthopyran or benzopyran compounds, are also described

135 citations

Journal ArticleDOI
TL;DR: The novel 6,7-disubstituted trans-3,4-dihydro-2, 2-dimethyl-4-pyrrolidino-(or piperidino)-2H-1-benzopyran-3-ols conferred superior antihypertensive activity to hydralazine and to the calcium antagonist, nifedipine, in SHR.
Abstract: A series of novel 6,7-disubstituted trans-3,4-dihydro-2, 2-dimethyl-4-pyrrolidino-(or piperidino)-2H-1-benzopyran-3-ols was prepared and tested for antihypertensive activity in the conscious spontaneously hypertensive rat (SHR) and compared with certain of their monosubstituted analogues. The potent blood pressure lowering activity of the 6-monosubstituted compounds was enhanced by incorporation of an acetylamino or amino group at C(7) and that of the 7-nitro-substituted compound by incorporation of an amino (but not an acetylamino group) at C(6). The combination of 6-nitro or 6-cyano with 7-(acetylamino) or 7-amino groups and 6-amino with 7-nitro groups in trans-4-pyrrolidino- or -4-piperidino-2,2-dimethyl-2H-1-benzopyranols conferred superior antihypertensive activity to hydralazine and to the calcium antagonist, nifedipine, in SHR. The synthetic route to these compounds involves the conversion of 2H-1-benzopyrans to bromohydrins that were treated with pyrrolidine or piperidine. Preparation of the 6-cyano-7-amino analogue was accomplished when 6-cyano-7-[(trifluoroacetyl)amino]-2,2-dimethylbenzopyran was used as starting material.

129 citations

Journal ArticleDOI
TL;DR: In this paper, a mesoporous aluminosilicate MCM-41 catalyst was used to accelerate the alkylation of 2,4-di-tert-butylphenol with cinnamyl alcohol.
Abstract: Owing to its large molecular size, alkylation of 2,4-di-tert-butylphenol with cinnamyl alcohol does not take plAcc using HY zeolite (pore opening 7.4 A) as catalyst even after controlled steaming treatment to increase its mesoporosity; by contrast, novel mesoporous aluminosilicate MCM-41 catalyses this reaction giving rise to 6,8-di-tert-butyl-2-phenyl-2,3-dihydro[4H]benzopyran (arising from intramolecular cyclization of the primary cinnamylphenol) together with 4-tert-butylphenol and small amounts of 6-tert-butyl-2-phenyl-2,3-dihydro[4H]benzopyran.

119 citations

Journal ArticleDOI
TL;DR: An expeditious construction of a benzopyran skeleton via Lewis acid-catalyzed C-H functionalization was achieved, affording the desired compounds in excellent chemical yields with short reaction times.

119 citations

Journal ArticleDOI
TL;DR: The first organocatalyzed asymmetric synthesis of chiral benzopyrans was reported in this article, where a domino reaction involving an oxa-Michael attack of salicylic aldehyde derivatives onto α,β-unsaturated aldehydes was performed.
Abstract: Benzopyrans, or chromenes, are widespread in nature and are considered to be a privileged scaffold in medicinal chemistry. Herein, we report the first organocatalyzed asymmetric synthesis of chiral benzopyrans. The benzopyran unit is constructed through a domino reaction involving an oxa-Michael attack of salicylic aldehyde derivatives onto α,β-unsaturated aldehydes, activated through iminium-ion formation with the organocatalyst, followed by an intramolecular aldol reaction and subsequent elimination of water. This overall reaction sequence provides benzopyrans with aromatic C-2 substituents in up to 60% yield and 60% enantioselectivity, while C-2 aliphatic analogues can be obtained in 90% enantiomeric excess, but with only 20% yield. The role of additives, as well as the possible racemization of the benzopyran, was also investigated.

112 citations


Network Information
Related Topics (5)
Aryl
95.6K papers, 1.3M citations
91% related
Cycloaddition
39.9K papers, 728.7K citations
90% related
Enantioselective synthesis
58.1K papers, 1.6M citations
89% related
Moiety
40K papers, 615K citations
88% related
Alkyl
223.5K papers, 2M citations
88% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20234
202220
202114
20209
201925
201814