Tris(2,4-di-tert-butylphenyl) phosphate

The title compound, C42H63O4P, was isolated from the leaves of Vitex negundo. Two of the tert-butyl groups are disordered over two orientations with occupancy ratios of 0.57 (1):0.43 (1) and 0.67 (1):0.33 (1). Several intramolecular C—H⋯O interactions are observed in the molecular structure.

The title compound, C 42 H 63 O 4 P, was isolated from the leaves of Vitex negundo. Two of the tert-butyl groups are disordered over two orientations with occupancy ratios of 0.57 (1):0.43 (1) and 0.67 (1):0.33 (1). Several intramolecular C-HÁ Á ÁO interactions are observed in the molecular structure.   Table 1 Hydrogen-bond geometry (Å , ). Diffraction data were collected at the G. N. Ramachandran X-ray data-collection facility in the Department. This work was funded by the Indian Council of Medical Research (ICMR), New Delhi.

Comment
Vitex negundo is one of the most common Indian medicinal plants which is used in Indian Folk medicine in the treatment of various ailments (Aswar et al., 2009). Though, almost all parts of V. negundo are used, the leaves and the barks are the most important in the field of medicine (Chadha, 1976). The roots of V. negundo was reported to have antifilarial activity (Sahare et al., 2008) and antihelmintic activity (Rastogi et al., 2009). The methanol extract of V. negundo leaves standardized in terms of total polyphenol content was reported to have good free radical scavenging activity and anti-inflammatory activity (Kulkarni et al., 2008). Many phenolic and polyphenolic compounds (secondary metabolites) were isolated from various plant sources so far, but the title compound is a new class of phenolic compound that has been isolated from the leaves of V. negundo, leading to an idea of new biosynthetic pathway of phenolics in plants and screening of their various biological activities for therapeutical approaches. It is a high molecular weight substituted phenolic compound. It is a class of primary anti-oxidant (free radical scavengers) which combines with peroxide radicals and breaks autocatalytic cycle. We report here its crystal structure.
In the title molecule ( Fig. 1), the O-P-O angles around the P atom deviate significantly from ideal tetrahedral values.

Experimental
Vitex negundo leaves were collected in Kolli Hills, Namakkal, during April, 2008 and were identified by a botanical expert.
Tris-(2,4-di-tert-butylphenyl)phosphate was isolated from the ethyl acetate extract of the leaves of V. negundo by silica gel column chromatography with gradient mixtures of hexane and ethyl acetate. White crystals were obtained by slow evaporation of an ethyl acetate solution. (m.p. 454 K-459 K).

Refinement
The C7 and C21 tert-butyl groups are disordered over two orientations, with occupancies of 0.567 (14) and 0.433 (14), and 0.668 (7) and 0.332 (7), respectively. The corresponding bond distances involving the disorderded atoms were restrained to be equal. The U ij components of the disordered atoms were approximated to isotropic behaviour. H atoms were positioned geometrically and allowed to ride on their parent C atoms, with C-H distances in the range 0.93-0.97 Å and with U iso (H) = 1.5U eq (C) for methyl H and 1.2U eq (C) for other H atoms. Fig. 1 (7) 0.109 (7)