2- hydroxystyrenes

PHOST represents poly(4-hydroxystyrene). The properties of the isomeric poly(2-hydroxystyrene) and poly(3-hydroxystyrenes) differ substantially (87). 

The analogy between oxygen and nitrogen could not be extended to the formation of 2//-benz[e ][ 1,2]oxaborins from styrenes treatment of 2-hydroxystyrene with boron halides gave only tars. However, tolan-2,2 -diboronic acid was cyclized in the presence of alkali to give a product whose structure was suggested to be (198) (59TL(14)21). 

Hydrodesulfnrisation of benzothiophenes is conveniently achieved using Raney nickel. Reduction of the hetero-rings of both benzofuran and benzothiophene giving 2,3-dihydro derivatives, notably with retention of the snlfur in the latter case, can be achieved using triethylsilane in acidic solution, or with hydrogen over colloidal rhodium. Reductive cleavage of benzofuran to 2-hydroxystyrene is caused by lithium with 4,4 -di-f-butylbiphenyl (DTBB). ... 

Under the dual catalysis of AgOAc and a chiral phosphoric acid, asymmetric annulation of 3-alkynylacrylaldehydes with 2-hydroxystyrenes affords complex multiring-fused chromans (14JOC7063). A variety of... 

Enantiopure polycyclic chromans arise from an asymmetric cascade annulation reaction of 2-hydroxystyrenes with o-alkynyl benzaldehydes or ketones (Scheme 34) (13JA11402). 

Scheme 3.29 Pd-catalyzed C-H carboxylation of 2-hydroxystyrenes to prepare coumarins.

Botteghi C, Paganelli S, Moratti F, Marchetti M, Lazzaroni R, Settambolo R, Piccolo O. Synthesis of 2-chromanol by hydroformylation of 2-hydroxystyrene derivatives. J. Mol. Cat. A Chem. 2003 200 147-156. 

Karrer and Schmid have examined the water-soluble constituents in poppy straw after extraction of the alkaloids, and have recorded the presence of -hydroxybenzaldehyde, vanillin, -hydroxystyrene, meconin and the following acids fumaric, dZ-lactic, benzoic, -hydroxycinnamic, p-hydroxybenzoic, 2-hydroxycinchoninic, vanillic, phthalic, hemipinic and m-hemipinic, with a more highly unsaturated, carboxylic acid J, b.p. 170-570-02 mm., and three unidentified substances Fa , m.p. 271-2° Wx, m.p. 310° (dec.) and Q, m.p. 260° the two latter are free from nitrogen and contain no methoxyl. 

The decarboxylation of 4-hydroxycinnamic acid to 4-hydroxystyrene, and of fernlic acid (3-methoxy-4-hydroxycinnamic acid) to 4-vinylgnaiacol by several strains of Haf-nia alvei and H. protea, and by single strains of Enterobacter cloacae and K. aerogenes (Fignre 2.7d) (Findsay and Priest 1975). The decarboxylase has been pnrihed from Bacillus pumilis (Degrassi et al. 1995). 

Foster, K. L. Baker, S. Brousmiche, D. W. Wan, P. o-Quinone methide formation from excited state intramolecular proton transfer (ESIPT) in an o-hydroxystyrene. J. Photochem. Photobiol. A Chem. 1999, 129, 157-163. 

This procedure has been used in the preparation of other nitrostyrenes in the following yields o-nitrostyrene (40%),2 / -nitrostyrene (41%),2 and 3-nitro-4-hydroxystyrene (60%).2 A better procedure for more volatile styrenes involves simultaneous decarboxylation and codistillation with quinoline from the reaction flask. This method has been used to prepare the following styrenes o-chlorostyrene (50%),3 4 m-chlorostyrene (65%),4 -chlorostyrene (51%),4 m-bromostyrene (47%),4 o-methoxystyrene (40%),4 -methoxystyrene (76%),4 m-cyano-styrene (51%),3 and j -formylstyrene (52%).9... 

Rhodococcus sp. Strain WU-K2R A Rhodococcus strain capable of sulfur-specific desulfurization of benzothiophene, naphthothiophene (NT), and some of their alkyl derivatives was reported [35]. The metabolites of BT desulfurization were BT sulfone, benzo[c][l,2]oxanthiin S-oxide, benzo[c][l,2]oxanthiin S,S-dioxide, o-hydroxystyrene, 2,(2 -hydroxyphenyl)ethan-l-al, and benzofuran. The NT metabolites were NT sulfone, 2 -hydroxynaphthyl ethene, and naphtho[2,l-b]furan [35], The exact biochemical pathway was not determined, however, part of the pathway for BT desulfurization was speculated to be similar to Paenibacillus All-2. 

The desulfurization pathway was proposed to be BT -> BT sulfone -> benzo[e][l,2]oxanthiin S-oxide -> o-hydroxystyrene. Additionally, formation of the intermediate benzo(e)(l,2)oxathiin S,S dioxide was inferred to a side pathway resulting in formation of benzofuran as shown in Fig. 7. This pathway is similar to that reported for Sinorhizobium KT55, Paenibacillus sp. strain All-2 and R. erythropolis KT462. 

Ruasse and Dubois (1984). Rate data for styrenes and a-Me-styrenes (from Durand et al., 1966) and for methoxy- and hydroxystyrenes (from Loudon and Berke, 1974). "Values in parentheses are for bromination in water (Ruasse and Lefebvre, unpublished results). Grunwald-Winstein coefficients for solvent effects. Values in parentheses are for protonation in MeOH (Toullec, 1979 Dubois et al., 1981b). Bronsted exponents. 

Heating pure TBMS, TBS and TBSS films at 130 C gave no volatile products. Pyrolysis at 725°C gave rise to both deprotection (as determined by the evolution of isobutene and carbon dioxide), and depolymerization to afford the respective monomers, sulfur dioxide, 4-hydroxystyrene, or 4-hydroxy-a-methylstyrene. The compounds, 4-hydroxystyrene and 4-hydroxy-a-methylstyrene, were identified on the basis of their mass spectra, which were consistent with those reported in the literature for these materials (22,23). Additionally, TGA analysis confirmed that all three polymers undergo complete volatilization upon heating to >400 C. 

Resist solutions of o-cresol novolac-siloxane copolymers were prepared as 15 w/v % solutions of the polymer in 2-methoxyethyl acetate using 20 wt % (based on polymer) of the positive sensitizer. Poly(hydroxystyrene) and 2-methyl resorcinol copolymers were spun into films from 2-methyl tetrahydrofuran. Solutions were filtered through successive 1.0, 0.5 and 0.2 pm filters and stored in... 

The thermal properties of the 2-methyl resorcinol, poly(hydroxystyrene) and the PDMSX copolymers prepared with them are shown in Table HI. For both copolymer systems using 4400 g/mole PDMSX blocks there was no significant... 

In another application, the diazonium salt (D1 or D2) (2.5 wt%) was dissolved in a mixture of cyclohexanone and acetic acid containing 12.5 wt% poly(4-hydroxystyrene) and 2. 5 wt% Methylone resin (GE 75108). The resist was exposed with a 600-W Xe-Hg lamp through a 313-nm interference filter. After exposure the resist was baked at 80V for 3 minutes and developed in a 1 wt% tetramethylammonium hydroxide aqueous solution. 

Figure 11. Exposure curve of the acid-catalyzed resist system consisting of poly(4-hydroxystyrene), D2, and...

Synthesis of the Polymers Containing Reactive Ether Pendant Groups, We have previously described the synthesis of high purity poly(p-hydroxystyrene) free from deleterious oxidized species by polymerization of 4-t-butyloxycarbonyloxy-styrene followed by the removal of... 

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