Process for the preparation of dihydropyrans

Details Process for the preparation of dihydropyrans Process for the preparation of dihydropyrans

1989-01-05

1992-11-10

Ivy, C. Warren

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

549381, C07D30918

Patent

active

051625512

ABSTRACT:
The invention provides a process for the preparation of 5,6-dihydro-2H-pyran derivatives, wherein an aldehyde of formula I: ##STR1## wherein R.sub.1 represents an alkyl, cycloalkyl, aralkyl, alkaryl or aryl group having at most 15 carbon atoms and a diene of formula II: ##STR2## wherein R.sub.2 and R.sub.3 represents a hydrogen atom or an alkyl group having 1-6 carbon atoms are reacted in a Diels-Alder-type reaction under the influence of an inorganic Lewis acid catalyst, producing a compound of formula III wherein R.sub.1 -R.sub.3 have the meaning given above. ##STR3## Preferably R.sub.1 represents a 1-6 carbon atom alkyl group, a phenyl group or an o-, m- or p-tolyl group. Isoprene or 2-methyl-1,3-pentadiene is preferably used as the diene. The preferred catalyst is AlCl.sub.3 or SnCl.sub.4 and an organic nitro compound may be used as the co-catalyst.

REFERENCES:
patent: 4163758 (1979-08-01), Kondo et al.
patent: 4837344 (1989-06-01), Miyaji et al.
Ansell et al, J. Chem. Soc., Chem. Comm., pp. 739-740 1972.
Falbe et al., Rompp Chemie Lexikon, pp. 956-957.
Organic Reactions, vol. 32, pp. 8-9, 1984.
Journal of Organic Chemistry, vol. 48, 1983, blz 3003-3010 Am. Chemical Society, Washington US Snider et al.
Monatshefte fur Chemie, vol. 107, 1976, blz 675-684--Springerverlag, DE; H. Griengl et al "Prins-Reaktionen mit Arylaldehyden".

Affiliated with

Also associated with

Rating

Process for the preparation of dihydropyrans does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process for the preparation of dihydropyrans, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the preparation of dihydropyrans will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2295165