Fragrance raw materials monographs 369

4-ISOPROPYL-1-METHYL-2-PROPENYLBENZENE

Synonym : Verdoracine. CAS Registry No. 14374-92-6 CAS Index Name: benzene, l-methyl-4-(1-methylethyl)-2-(1-propenyl)-

Structure:

CH3

~ CH : CH. CH3

CH3 CH3

Description: A clear liquid. Occurrence: Has apparently not been reported to occur in nature. Preparation: By Friedel-Crafts acylation of p-cymene with propionyl chloride followed by reduction and dehydration. Physical properties:

Refractive index 1.527 Specific gravity 0.889

(Analytical data on the material as tested by RIFM.) Gas chromatogram and infra-red curve on file at RIFM.

Biological data

Acute toxicity. The acute oral LDs0 in rats and the acute dermal LDs0 in rabbits exceeded 5.0 g/kg (Moreno, 1980) with 1/10 deaths in rats at that dose and 0/10 deaths in rabbits,

Irritation. As part of an acute dermal LDs0 study, the undiluted material produced slight to severe irritant effects, and scaly and crusted skin at necropsy with rabbits patch-tested for 24 hr under occlusion at a dose of 5.0 g/kg (Moreno, 1980).

A 48-hr closed-patch test at a concentration of 6% in petrolatum on the backs of 30 volunteers produced no irritation (Epstein, 1980).

Sensitization. A maximization test (Kligman, 1966; Kiigman & Epstein, 1975) was carried out on 30 volunteers. The material was tested at a concentration of 6% in petrolatum and produced no sensitization reactions (Epstein, 1980). This test concentration was based on a reported maximum concentration of 0.6% in consumer products.

References

Epstein, W. L. (1980). Report to RIFM, 25 June. Kligman, A. M. (1966). The identification of contact allergens by human assay. III. The maximization test. A procedure

for screening and rating contact sensitizers. J. invest. Derm. 47, 393. Kligman, A. M. & Epstein, W. (1975). Updating the maximization test for identifying contact allergens. Contact Dermatitis

l, 231. Moreno, O. M. (1980). Report to RIFM, 30 August.