Dibenzopyrane

The chemical name of A9-THC according to the dibenzopyrane numbering system is 3-pentyl-6,6,9-trimethyl-6fl,7,8,10fl-tetrahydro-6H-dibenzo-[b, d]pyran-l-ol as depicted in 1.1 (Fig. 1). 

A -THC, the main psychoactive component of cannabis, is a moderately potent partial agonist of the CBi and CB2 receptors, while cannabidiol has little affinity for either receptor (Table 6.7). The term classical cannabinoids is used to describe cannabinoid receptor modulators structurally related to (67), which have a tricyclic dibenzopyran core. While several other structural types of cannabinoid receptor modulators have been discovered in recent years, the classical cannabinoids are still by far the most extensively studied group in terms of SAR and pharmacology. 

Intramolecular cyclization of 2-lithiobenzyl-2-halophenyl amines, ethers, and thioethers—Synthesis of phenanthridine, dibenzopyran, and dibenzothiopyran derivatives Having demonstrated the efficiency of this methodology for the preparation of indole derivatives, we prepared the 2-fluoro-phenyl ether and thioether 22 a, b to study their potential as substrates that could afford oxygen and sulfur heterocycles. However, treatment of 22 a, b with fBuLi afforded, after... 

Table 3. Preparation of functionalized derivatives of dihydrophenanthridines 26-28, dibenzopyrans 29 and 33, and dibenzothiopyrans 30, from 2-bromobenzyl compounds 25 and 32.

Adams R, Baker BR, Wearn RB, Structure of Cannabinol. 111. Synthesis of Cannabinol,l-Hydroxy-3-n-amyl-6,6,9-trimethyl-6-dibenzopyran, J Amer Chem Soc 62 2204-2207 1940. 

Furfural, 5-methyl EO Furo-(l,2,A)-4-N-pentyl-7-7-10-trimethyl-dibenzopyran, 2-methyl Lf (smoke) Furo-(l,2,A)-4-N-pentyl-7-7-10-trimethyl-dibenzopyranyl Lf (smoke) ... 

LSD and the anticholinergics were the subjects of earlier extensive evaluations.2,3 this chapter Is concerned only with phencyclidine and dlmethylheptylpyran (dibenzopyran) and its isomers. 

REVIEW OF AVAILABLE INFORMATION ON DIBENZOPYRANS DIMETHYLHEPTYLPYRAN AND RELATED COMPOUNDS... 

The doses of the dibenzopyrans used at Edgewood were similar to those used by other investigators. Lemberger e t al. 0 used DMHP at 200 vg per 70 kg Intravenously, for example. The severe postural hypotension that occurs when the drug is taken intravenously, intramuscularly, or orally is a limiting factor in giving hallucinogenic amounts of DMHP isomers. 

Cannabis resin, obtained from the flowering tops of hemp plants, contains a number of dibenzopyrans. The main active constituent is (-)-A1-3,4-numbering system is used). Cannabinol derivatives have slight pharmaceutical potential, e.g. as antiemetics and analgesics, but because of their hallucinatory effects and habituation tendency, which have led to their widespread abuse, they are not prescribed. 

Formation of the isochroman system is considered to trigger the synthesis of the dibenzopyran (17, X = H2) by the acid catalysed cyclisation of c/s-enediynes (16, X = H2). In a similar manner, the carboxyl function in (16, X = O) promotes cylisation to a dihydropyranone derivative which is followed by a Myers cycloaromatisation to the dibenzopyranone (17, X = O) (95TL9165). 

Scheme 4. General mechanistic pathway of the domino process to dibenzopyrane 2 (additional ligands omitted).

The reaction of isatin 7 with acylated dibenzothiophene [81, 109, 116], dibenzofuran [116], and dibenzopyran [72] with the general formula 124 and also the reaction of the isatins 59 with acetylphenothiazine [72] and acetylthianthrene [117] with the general formula 125 gave the corresponding quinolinecarboxylic acids 126 and 127, having a tricyclic condensed system with a heterocycle as substituent at position 2. 

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