Propyl benzene, synthesis

Cymene. i-Methyl 4-Iso-propyl Benzene.—Cymene, the only other isomeric hydrocarbon of the composition C10H14, which we shall consider, is shown to be i-methyl 4-iso-propyl benzene, by its synthesis from para-brom toluene and isopropyl bromide. 

Transition metal catalysts can also be used in photochemical organic synthesis. For example, the photo-Bergman reaction (cycloaromatization see also Scheme 6.62) of (Z)-hex-3-en-l,5-diyne [(Z)-589], which is obtained by photostationary E Z isomerization (Section 6.1.1) from ( )-589, occurs via transition metal-catalysed cycloaromatization reaction followed by photochemical dissociation of the arene ligand from the complex 590 (Scheme 6.289).1530 The product, 1,2-di( -propyl)benzene (591), is obtained in 91% chemical yield. 

The lUPAC name of cannabidiol is 2-[(lS, 6iI)-3-methyl-6-prop-l-en-2-yl-l-cyclohex-2-enyl]-5-pentyl-benzene-1,3-diol. Cannabidiol (CBD, 2.9) in its acidic form cannabidiolic acid (CBDA, 2.10) is the second major cannabinoid in C. sativa besides A9-THC. As already mentioned for A9-THC, variations in the length of the side chain are also possible for CBD. Important in this context are the propyl side chain-substituted CBD, named cannabidivarin (CBDV, 2.11), and CBD-C4 (2.12), the homologous compound with a butyl side chain. Related to the synthesis starting from CBD to A9-THC as described in Sect. 3.1, it was accepted that CBDA serves as a precursor for THCA in the biosynthesis. Recent publications indicate that CBDA and THCA are formed from the same precursor, cannabigerolic acid (CBGA), and that it is unlikely that the biosynthesis of THCA from CBDA takes place in C. sativa. 

Unlike alkylation, acylation is controlled easily to give monosubstitution, because once an acyl group is attached to a benzene ring, it is not possible to introduce a second acyl group into the same ring. Because of this, a convenient synthesis of alkylbenzenes starts with acylation, followed by reduction of the carbonyl group with zinc and hydrochloric acid (Section 16-6). For example, propylbenzene is prepared best by this two-step route because, as we have noted, the direct alkylation of benzene with propyl chloride produces considerable amounts of isopropylbenzene and polysubstitution products ... 

An efficient synthesis of (R)- and (S)-1 -amino-2,2-difluorocycloropanecarboxylic acid (DFACC) 91 via lipase-catalyzed desymmetrization of prochiral diols 89 and prochiral diacetates 92 was recently reported.28 Thus, the lipase-catalyzed transesterification of 89 using vinyl acetate as acyl donor in benzene di-z-propyl ether (20 1) as organic solvent... 

The transformation of raw materials into products of greater value by means chemical reaction is a major industry, and a vast number of commercial prod is obtained by chemical synthesis. Sulfuric acid, ammonia, ethylene, propyl phosphoric acid, chlorine, nitric acid, urea, benzene, methanol, ethanol, ethylene glycol are examples of chemicals produced in the United States, billions of kilograms each year. These in turn are used in the large-scale manu ture of fibers, paints, detergents, plastics, rubber, fertilizers, insecticides, Clearly, the chemical engineer must be familiar with chemical-reactor design operation. 

Problem 24.8 The //-propyl ether of 2-amino-4-nitrophenol is one of the sweetest compounds ever prepared, being about 5000 times as sweet as the common sugar sucrose. It can be made from the dinitro compound by reduction with ammonium bisulfide. Outline the synthesis of this material starting from benzene or toluene and any aliphatic reagents. 

For the synthesis of end-functionalized block copolymers with one dimethyl-amino end group 3-(Dimethylamino)propyl lithium (DMAPli) was used as initiator, in a nonpolar solvent (i.e., benzene). The diblocks were prepared by sequential addition of monomers starting with the block to which the end... 

Charles Friedel (Strasbourg, 12 March 1832-Montauban, 20 April 1899) was (1876) professor of mineralogy in the Sorbonne and succeeded Wurtz as professor of organic chemistry in the Sorbonne (1884-99). With James Mason Crafts (Boston, 1839-Ridgefield, Conn., 20 June 1917), professor in and later president of the Massachusetts Institute of Technology, he discovered the use of aluminium chloride in reactions of synthesis, e.g. of homologues of benzene. Friedel prepared a number of artificial minerals (quartz, tridymite, rutile, etc.), often in collaboration with Edmund Sarasin, from 1879. FriedeFs discovery of secondary propyl alcohoF verified Kolbe s prediction of its... 

Once again, it is attached by the first carbon because a rearrangement does not occur (the acyUum ion is resonance stabilized, and does not rearrange). Now, aU we need is a way to remove the oxygen, and then we will have a two-step synthesis for instaUing a propyl group on a benzene ring ... 

Propose a synthesis of 5-propyl-l,3-benzenediamine, starting from benzene. (Caution Consider carefully the order in which you introduce the groups.)... 

While the diazonium salt route is probably the most commonly used laboratory synthesis of phenols, phenol itself is manufactured from wo-propylbenzene, which has the common name cumene. Cumene is prepared by a Friedel-Crafts reaction between propene and benzene, in the presence of a strong acid such as H3PO4 (Figure 13.28). The key intermediate is the 2-propyl cation, formed by protonation of propene. 

---