Über die Enolate der o ‐Oxy‐diphenyl‐essigsäure‐lactone. (Mitbearbeitet von H. Lang und W. Jacobus)

Abstract

2. .\us 8.1 g S a f r o l und 16.3 g R r o m -t r ' l n i t r o -m e t h a n (1.42 1101.) in I 50 ccm M e t h y 1 a 1 ko h o le) gelost , f) -M e t h o x y -yb r o md i h q' d r 0.s a f r o l , C,H,[CH,.CH(OCfi,) .CH,.Br 1(Q,CH,)5*4, das, unter 0.5 mm Druck destilliert, neben einigen Tropfen Vorlauf in einer Ausbeute von 1s.S g (= 93.8 ':o d. Th.) erhalten wird. . Xochmals destilliert, geht die l'erbindung unter 0.8 mm Druck bei 138-139O (1:. i. D., Olbad-Temp. etwa 160") als farbloses, analysenreines 01 uber. , , ' ?U : -1.5595; dp 2 1.4672. --C,,H,,O,'Brl~$. Ber. M D 59189. Gef. MI) 60.12. 3. Aus 7.4 g, o -E s d r a g o l und 16.3 g B r o m -t r i n i t r o -m e t h a n (1.42 Mol.) in 150 ccm M e t h y l a l k o h o l gelost, $-Methoxy-y-bromd i.h y d r oe s d r ago1 (o ) , C,H,[CH2. CH(OCH,) . CH,. Br] '(OCH,) 2, in einer Ausbeute von 11.3 g (:-: 87% d. Th.). Farbloses 01. Sdp.o.l 101-1030 (F. i. D., Olbad-Temp. etwa 145~). . ' E = 1.5428: do =: 1,3570. --C,,H,,O,'Br'a. Ber. 111, 60.45. Gef. BID 60.16. 4. Aus 7.4 g p -E s d r a g o l und 16.3 g B r o m -t r i n i t r o -m e t h a n (1.42 hlol.) in ,150 ccm M e t h y l a l k o h o l gelost, P-Methoxy-y-brom-dihydroesdragol(-p), C,,H,[CH,.CH(OCH,).CH,. Br]1(OCH,)4, neben etwa I g Vorlad in einer Ausbeute von 10.2 g (= 78.8% d. Th.). Farbloses 01. Sdp.,,, 126-1270 (1;. i. D., Olbad-Temp. etwa 160~).

Fundamental processes of autoxidation

“…However, some radicals, usually those with outstanding resonance stability, are stable to oxygen. For example radicals such as are inert to oxygen (11,IB). In these eases resonance structures involving the presence of the odd electron on oxygen may be considerably more stable than other resonance forms and the radicals may more properly be considered to be an alkoxy or phenoxy radical.…”

Synthesis of 2,3-dihydrobenzofuran-2-ones and 2,3-dihydrobenzothiophen-2- and 3-ones by rearrangements of 3-hydroxy analogs

“…The 1 H NMR spectra of these products show no signals corresponding to those assigned to the Nsubstituted benzotriazole groups of intermediates 9a-h (7.2-8.1 ppm). The 13 C NMR spectra of these compounds also no longer show signals for a N-substituted benzotriazole group (in this particular case our assignments were based on signals with chemical shifts around 120 ppm and 146 ppm) and carbonyl carbon (in the range 195-196 ppm) of 9a-h.…”

“…The disappearance of the singlet signals at 3.05 ppm (15c') and 4.21 ppm (15c'') in the spectra of diastereoisomers 15c after the addition of D 2 O suggested the presence of hydroxy groups. In the 13 C NMR spectra of diastereoisomers 15c, the signal at 195.8 ppm corresponding to the carbonyl group in 14c, as well as a signal at 62.4 ppm assigned to the carbon between benzotriazolyl group and sulfur in 14c are no longer present. The new signals at 90.2 ppm, 87.5 ppm in 13 C NMR spectrum of the major diastereoisomer 15c', as well as at 90.3 ppm, 86.3 ppm in the spectrum of the minor isomer 15c'', were assigned to the C-2 and C-3 carbons of the 2,3-dihydrobenzothiophene ring in 15c.…”

“…We isolated intermediate 10a (82%, single isomer) to support the proposed reaction pathway (Scheme 2). The structure of 10a was deduced from its 1 H NMR, 13 C NMR spectra (see experimental section). The 1 H NMR spectrum of 10a shows no signals assigned to ethoxy group protons of 9a (doublet at 1.8 ppm and multiplet in the range 6.92-7.08 ppm), but shows a singlet at 1.77 ppm assigned to the 2-methyl group and a singlet at 3.03 ppm assigned to the 3-hydroxy group of 10a.…”

“…10 3-Alkyl-3-aryl-2,3-dihydrobenzofuran-2-one derivatives also possess antispasmodic, 11 antihypoxic, 12 and nootropic activity. 12 Previously reported synthetic routes to 2,2-disubstituted 2,3-dihydrobenzofuran-3-ones include (Scheme 4): (i) condensation of phenols with (a) 2-hydroxycarboxylic acids 13 or (b) acrylic esters; 14 (ii) hydrolysis -cyclization of 2-methoxyphenylacetonitriles in the presence of hydrobromic acid; 10 (iii) acid-catalyzed condensation of phenols with 2-oxo-carboxylic acids; 15 (iv) oxidative decyanation; No preparation of 3-alkyl-3-aryl-2,3-dihydrobenzothiophen-2-ones has been previously reported.…”