Propionic 2-bromo-3-phenyl

The reaction of potassium 3-amino-4-oxo-3,4-dihydroquinazoline-2-thiolate 62 with a-bromophenylacetic acid 63 resulted in the formation of (3-amino-4-oxo-3,4-dihydroquinazolin-2-ylsulfanyl)-phenyl-acetic acid methyl ester 64 which on alkali treatment and subsequent acidification resulted in the synthesis of 2-phenyl- 1-thia-4,4a,9-triaza-anthracene-3,10-dione 65 <1999JCR(S)86>. Similarly, the reaction of potassium 3-amino-5,6-dimethyl-4-oxo-3,4,4a,7a-tetrahydrothieno[2,3- pyrimidine-2-thiolate 66 with a-bromo-ester 67 resulted in the formation of 2-(3-amino-5,6-dimethyl-4-oxo-3,4,4a,7a-tetrahydrothieno[2,3- / pyrimidin-2-ylsulfanyl)-propionic acid ethyl ester 68. Subsequent treatment with alkali followed by acidification resulted in the formation of 2,3,7-trimethyl-3a,9a-dihydro-l,8-dithia-4a,5,9-triazacyclopenta[ ]naphthalene-4,6-dione 69 <2000JHC1161>... 

Miktoarm stars of the A(BC)2 type, where A is PS, B is poly(f-bulyl acrylate) (PtBA), and C is PMMA [161] have been synthesized, by using the trifunctional initiator 2-phenyl-2-[(2,2,6,6-tetramethyl)-l-piperidinyloxy] ethyl 2,2-bis[methyl(2-bromopropionato)] propionate (NMP, ATRP) (Scheme 86). In the first step, a PS macroinitiator with dual < -bromo functionality was obtained by NMP of styrene in bulk at 125 °C. This precursor was subsequently used as the macroinitiator for the ATRP of ferf-bulyl acry-... 

Bromination of cinnamic acid with NBS in aq. MeOH gives 2-bromo-3-methoxy-3-phenyl propionic acid, PhCH(0Me)CHBrC02H. At moderately high [H+] the reaction is second-order and independent of [H+], whereas at low [H+] the rate increases with decrease in [H+], Succinimide inhibits the reaction182. 

A solution of 4-[2-(5-ethyl-2-pyridyl)ethoxy]nitrobenzene (60.0 g) in methanol (500 ml) was hydrogenated at room temperature under one atmospheric pressure in the presence of 10% Pd-C (50% wet, 6.0 g). The catalyst was removed by filtration and the filtrate was concentrated under reduced pressure. The residual oil was dissolved in acetone (500 ml)-methanol (200 ml). To the solution was added a 47% HBr aqueous solution (152 g). The mixture was cooled, to which was added dropwise a solution of NaN02 (17.3 g) in water (30 ml) at a temperature not higher than 5°C. The whole mixture was stirred at 5°C for 20 min, then methyl acrylate (112 g) was added thereto and the temperature was raised to 38°C. Cuprous oxide (2.0 g) was added to the mixture in small portions with vigorous stirring. The reaction mixture was stirred until nitrogen gas evolution ceased, and was concentrated under reduced pressure. The concentrate was made alkaline with concentrated aqueous ammonia, and extracted with ethyl acetate. The ethyl acetate layer was washed with water and dried (MgS04) The solvent was evaporated off to leave methyl 2-bromo-3- 4-[2-(5-ethyl-2-pyridyl)ethoxy]phenyl propionate as a crude oil (74.09 g, 85.7%). 

A mixture of the crude oil of methyl 2-bromo-3- 4-[2-(5-ethyl-2-pyridyl)ethoxy]phenyl propionate (73.0 g) thiourea (14.2 g), sodium acetate (15.3 g) and ethanol (500 ml) was stirred for 3 hours under reflux. The reaction mixture was concentrated under reduced pressure, and the concentrate was neutralized with a saturated aqueous solution of sodium hydrogencarbonate, to which were added water (200 ml) and ether (100 ml). The whole mixture was stirred for 10 min to yield 5- 4-[2-(5-ethyl-2-pyridyl)ethoxy]benzyl -2-imino-4-thiazolidinone as crystals (0.3 g, 523.0%). Recrystallization from methanol gave colorless prisms, melting point 187°-188°C, dec. 

Finally, stereochemical or simply chemical considerations have led several authors to postulate the formation of a p-lactone whenever they have had to deal with a reaction involving ammonia or an amine in aqueous or alooholic solution and a P-halo aoid. Some of the older literature on this subject has been discussed by Darapsky and others, > notably the formation of 3-phenylhydracrylamidu by t-hc reaction of ammoDium hydxosidc with 3-bromo-3-phenyl-propionic acid ... 

Figure 12.17 Several multifunctional initiators used for making star (co)polymers. (VIII) 2-((2,2-bis(hydroxymethyl) butoxy) carbonyl)-2-methylpropane-l,3-diyl bis(2-bromo-2-methyl propanoate) (Yang etal.,2008). (IX) l,l,l-tris(4-(2-bromoisobutyryloxy) phenyl) ethane (Matyjaszewski etal., 1999). (X) 2-(hydroxymethyl)-2-methyl-3-oxo-3-(2-phenyl-2-(2,2,6,6-tetramethyl piperidin-l-yloxy)ethoxy) propyl pent-4-ynoate (Altintas et al., 2008). (XI) propargyl 2-hydroxylmethyl-2-(or-bromoisobutyryloxymethyl)propion-ate (Altintas et al., 2008).

Interestingly, it appears that the nature of the substituent determines the stereochemical outcome of the reaction, since ethyl 2-bromo-2-phenyl-propionate itself gave the trans isomer exclusively. In contrast, reaction in the cases where R was an alkyl group gave the cis isomers as the predominant product. This was reasoned to arise from the nature of the zinc enolate formed. 

---