3500
. . . A M O N G SOME 43213
ORGANICS
4-Nitro-o-phenylenediamine M P 201-202°.
25g. ..$2.50
100 g. ..$8.40
N0 2 C6H 3 (NH 2 )2 . . .MW 153.14
F a r from the madding crowd's ignoble strife and to the eternal boredom of sophomores, a m a n named Thomas Gray published in 1751 some thoughts about Life inspired by the country churchyard of Stoke Poges in Buckingham shire. From the same town, exactly 200 years later, two other individuals whose thoughts about Life were more along the line of what part α-keto acids might play in it, sent to the editor of The Biochemical Journal (52,38) a paper i p which they introduced l,2-diamino-4-nitrobenzene as a reagent for these acids, proclaiming it more specific than the previous favorite, 2,4-dinitrophenylhydrazine, because it forms stable nitroquinoxalinols which 7151
may b e separated by paper chromatography. Actually this new reagent h a s been slumbering peace fully i n our catalog for the past 16 years ever since w e be gan making it as an intermediate toward a benzimidazole. A change of name in the interim toward the Chemical Ab stracts form, 4-Nitro-o-phenylenediamine, has made the grave a little harder to find. N o w t h e clarion call from S t o k e Poges, reinforced by an abstract we offer of a paper in The Analyst for August '55 on the use of the rea gent i n detecting a n d determining α-keto acids in blood and urine, brings life again to the old amine.
Maleo-pimaric Acid
100 g. . .$3.00 Til
Γ
CH2CH2CeH7(CH3)2(CO0H)CHCH2CHC[CH(CH3)2] :CHCCHCHCOOCO .
L
.MW 400.52
J
When the bark of a longleaf pine is scraped down into the sapwood, the wound exudes an item of commerce called gum oleoresin.. This consists of a mixture of a- and β-pinenes, sold as gum turpentine, plus a mixture of the following resin acids: HaC^COsH
H 3 C_C0 2 H
electric signs. If you d o your work in the cold, you'll find that levopimaric acid is the largest single c o m p o nent o f these resin acids; it is particularly dominant In e a r l y spring sap. The levopimaric acid—and only the levopimaric acid—re acts exothermically with maleic anhydride, Diels-Alderv/ise, t o yield our new Eastman 7151 :
ax ^
H S C,CO 2 H
,CH 3
CH3 obietic acid HsC
"CH3
neoabietic acid
HJCCO2H
