493-08-3

Basic information

• Product Name: 3,4-Dihydro-(1H)-benzopyrane
• Synonyms: 3,4-Dihydro-(1H)-benzopyrane;Chromane;3,4-Dihydro-2H-1-benzopyran;Dihydrobenzo[b]pyran;3,4-dihydro-2H-chromene;2H-1-Benzopyran, 3,4-dihydro-;3,4-Dihydro-1H-benzopyran;Benzoxan
• CAS NO: 493-08-3
• Molecular Formula: C₉H₁₀O
• Molecular Weight: 134.1751
• Mol File: 493-08-3.mol
• Article Data: 10

Chemical Properties

• Melting Point: 4.8°C
• Boiling Point: 215°C (estimate)
• Flash Point: 76.2°C
• Appearance: /
• Density: 1.0720
• Vapor Pressure: 0.224mmHg at 25°C
• Refractive Index: 1.5444
• Storage Temp.: 2-8°C
• CAS DataBase Reference: 3,4-Dihydro-(1H)-benzopyrane(CAS DataBase Reference)
• NIST Chemistry Reference: 3,4-Dihydro-(1H)-benzopyrane(493-08-3)
• EPA Substance Registry System: 3,4-Dihydro-(1H)-benzopyrane(493-08-3)

Safety Data

• Hazardous Substances Data: 493-08-3(Hazardous Substances Data)

Usage

Definition

ChEBI: A benzopyran consisting of a pyran ring having a benzene ring ortho-fused across positions 2 and 3.

Synthesis Reference(s)

The Journal of Organic Chemistry, 46, p. 1384, 1981 DOI: 10.1021/jo00320a032

InChI:InChI=1/C9H10O/c1-2-6-9-8(4-1)5-3-7-10-9/h1-2,4,6H,3,5,7H2

Upstream product

• 254-04-6 2H-chromene 
• 254-03-5 4H-1-benzopyran 
• 122-97-4 3-Phenyl-1-propanol 
• 60956-33-4 3-phenylpropyl hydroperoxide 
• 588-63-6 3-phenoxypropyl bromide 
• 87841-77-8 2-(2-Phenoxy-ethylazo)-prop-2-yl-hydroperoxide 
• 109-92-2 ethyl vinyl ether 
• 110-82-7 cyclohexane 
• 1745-81-9 o-Allylphenol 
• 81246-41-5 C₁₆H₁₈NO₃S⁽¹⁺⁾*BF₄^(1-) 
• 60333-75-7 O-allyl-2-bromophenol 

Downstream Products

• 3875-78-3 6-bromo-chroman 
• 55745-97-6 3,4-dihydro-2H-1-benzopyran-6-carbaldehyde 
• 101019-00-5 chroman-6-yl-phenyl ketone 
• 21763-04-2 3,4-dihydro-4-phenyl-2H-chromene 
• 58621-52-6 1-<6-(3,4-dihydro-2H-1-benzopyranyl)>ethanone 
• 101019-06-1 1-chroman-6-yl-2-phenyl-ethanone 
• 271-89-6 1-benzofurane 
• 95-48-7 ortho-cresol 
• 13524-73-7 3-methyl-2,3-dihydrobenzofuran 
• 100-41-4 ethylbenzene 
• 101019-07-2 (E)-1-Chroman-6-yl-3-phenyl-propenone 
• 101019-03-8 Chroman-6-yl-(4-fluoro-phenyl)-methanone 
• 101019-04-9 (4-Chloro-phenyl)-chroman-6-yl-methanone 
• 101019-09-4 6-(4-Phenylbutyryl)dihydrobenzopyran 

Relevant articles and documents

Photoredox catalysis on unactivated substrates with strongly reducing iridium photosensitizers

Photoredox catalysis has emerged as a powerful strategy in synthetic organic chemistry, but substrates that are difficult to reduce either require complex reaction conditions or are not amenable at all to photoredox transformations. In this work, we show that strong bis-cyclometalated iridium photoreductants with electron-rich β-diketiminate (NacNac) ancillary ligands enable high-yielding photoredox transformations of challenging substrates with very simple reaction conditions that require only a single sacrificial reagent. Using blue or green visible-light activation we demonstrate a variety of reactions, which include hydrodehalogenation, cyclization, intramolecular radical addition, and prenylationviaradical-mediated pathways, with optimized conditions that only require the photocatalyst and a sacrificial reductant/hydrogen atom donor. Many of these reactions involve organobromide and organochloride substrates which in the past have had limited utility in photoredox catalysis. This work paves the way for the continued expansion of the substrate scope in photoredox catalysis.

Intermediates for use in the preparation of vitamin e

Novel intermediate compounds which can be used in the preparation of phytone and Vitamin E and a process for the preparation thereof. A process for the preparation of phytone and Vitamin E from these compounds is also claimed.

Photochemistry of o-Allylphenol. Identification of the Minor Products and New Mechanistic Proposals

The photochemistry of o-allylphenol (1) in cyclohexane has been reinvetigated.Besides the previously reported cyclic ethers 2 and 3, seven additional minor photoproducts have been detected.Spectroscopic methods, coupled with independent synthesis, have allowed their identification as 2-methylbenzofuran (5), o-propylphenol (8), the epoxide 4, the dihydroxy compound 9, the cyclohexyl ether 6, o-(cyclohexylmethyl)phenol (10), and the dimer 7.Their formation is rationalized through new mechanistic pathways, which involve initial intermolecular electron and/or proton transfer between two molecules of o-allylphenol, as well as di-?-methane rearrangement.Key intermediates appear to be radical V, carbenium ion IX, and carbene XI.This is supported by photolysis of o-allylphenyl acetate (11), which leads to the formation of a radical pair, followed by in cage recombination to the photo-Fries products 12 and 13 or, alternatively, diffusion of the radicals out of the solvent cage to afford the minor products 2, 5, and 6, identical to those obtained by photolysis of 1.