Physicochemical characteristic of Exudate of Dacryodes edulis

The Present work deals with the study of exudate of Dacryodes edulis with regards to various seasonal physicochemical properties of the purified solids exudate, acid hydrolysis product and saponification product like charring temperature (oC) (195.73 ± 4.75, 190 ± 7.9, 190 ± 3.4, ); flash point (oC) (105 ± 5.0, 100 ± 7.9, 100 ± 3.4); moisture content % (1.32 – 1.35, 1.05 – 1.08, 1.00 - 1.10); ash content (%) (1.77 – 1.85, 1.21 – 1.31, 1.26 -1.37); lignin content (%) (7.77 – 7.85, 6.21 – 6.31, 5.26 – 5.37); electrical conductivity (μS/cm) (28.40 -29.20, 32.10 – 33.00, 30.30 – 30.90); density (g/cm3) (0.76 -0.77, 0.94 – 0.98, 0.88 – 0.98); melting point (oC) (61.08 – 73.35, 58.69 – 73.35, 55.35 – 65.67). The physicochemical characteristic of Dacryodes edulis is found to be fluctuated with seasonal variations during the present investigation. The correlation coefficient showed positive relationship among the properties. The study reveals that exudate of Daryodes edulis can be tapped in large quantity in the dry season and is rich in lignin content but the seasons does not affect the properties.

S-Alkylated/aralkylated 2-(1H-indol-3-yl-methyl)-1,3,4- oxadiazole-5-thiol derivatives. 1. Synthesis and characterization

Purpose: To synthesize and characterize S-alkylated/aralkylated 2-(1H-indol-3-ylmethyl)-1,3,4- oxadiazole-5-thiol derivatives. Methods: 2-(1H-indol-3-yl)acetic acid (1) was reacted with absolute ethanol and catalytic amount of sulfuric acid to form ethyl 2-(1H-indol-3-yl)acetate (2) which was transformed to 2-(1H-indol-3- yl)acetohydrazide (3) by refluxing with hydrazine hydrate in methanol. Ring closure reaction of 3 with carbon disulfide and ethanolic potassium hydroxide yielded 2-(1H-indol-3-ylmethyl)-1,3,4-oxadiazole-5- thiol (4) which was finally treated with alkyl/aralkyl halides (5a-u) in DMF and NaH to yield Salkylated/ aralkylated 2-(1H-indol-3-ylmethyl)-1,3,4-oxadiazole-5-thiols (6a-u). Structural elucidation was done by IR, 1H-NMR and EI-MS techniques Results: 2-(1H-indol-3-ylmethyl)-1,3,4-oxadiazole-5-thiol (4) was synthesized as the parent molecule and was characterized by IR and the spectrum showed peaks resonating at (cm-1) 2925 (Ar-H), 2250 (S-H ), 1593 (C=N ) and 1527 (Ar C=C ); 1H-NMR spectrum showed signals at δ 11.00 (s, 1H, NH-1ʹ), 7.49 ( br.d, J = 7.6 Hz, 1H, H-4\'), 7.37 (br.d, J = 8.0 Hz, 1H, H-7\'), 7.34 (br.s, 1H, H-2\'), 7.09 (t, J = 7.6 Hz, 1H, H-5\'), 7.00 (t, J = 7.6 Hz, 1H, H-6\') and 4.20 (s, 2H, CH2-10ʹ). EI-MS presented different fragments peaks at m/z 233 (C11H9N3OS)˙+ [M+2]+, 231 (C11H9N3OS)˙+ [M]+, 158 (C10H8NO)+, 156 (C10H8N2)˙+, 130 (C9H8N)+. The derivatives (6a-6u) were prepared and characterized accordingly. Conclusion: S-alkylated/aralkylated 2-(1H-indol-3-ylmethyl)-1,3,4-oxadiazole-5-thiols (6a-u) were successfully synthesized.