Isopropyl group The

The NMR spectrum of isopropyl chloride (Figure 13 17) illustrates the appearance of an isopropyl group The signal for the six equivalent methyl protons at 8 1 5 is split into a doublet by the proton of the H—C—Cl unit In turn the H—C—Cl proton signal at 8 4 2 IS split into a septet by the six methyl protons A doublet-septet pattern is char acteristic of an isopropyl group... 

Phenyluracils with alkyl groups substituted in the 5- and 6-positions, such as (L), are reported to have analgesic and antipyretic activity [376, 377]. The 1-position may also be alkylated. Such compounds are prepared by the treatment of a-alkyl-/3-aminocrotonates with phenyl isocyanate. When the 5-substituent is an isopropyl group, the resulting compound is a sodiuretic without increase in potassium excretion. 

Thiazoles are less electron-rich isosteres of pyridines and therefore it was speculated that compounds with such substitution may have improved metabolic stability [30]. The modeling of A-82200 in which the N-terminal pyridinyl group was substituted by a 4-thiazolyl moiety indicated that the 5-membered ring binds in the S3 subsite and can be further derivatized at the 2 position by an isopropyl group. The isopropyl functionality makes van der Waals contacts with Val82 and fills the hydrophobic part of the S3 subsite in nearly optimal fashion. 

Catalysis over Typical Zeolites - In the alkylation of naphthalene, a-alkylation occurs in the initial stage because -positions are more reactive than P-positions. However, the (3/a ratio in the product mixture increases with the increase of reaction temperature and time on stream. Figure 8 shows the three reaction paths for producing diisopropylnaphthalene (DIPN) isomers. The reactions are (1) alkylation, (2) isomerization, and (3) transalkylation. Isomerization and transalkylation accompany the rearrangement of isopropyl groups. The zeolite type and reaction conditions, e.g., temperature and time on stream, usually determine the type of reaction path.4... 

Isopropylation over HY, HL and Other Zeolites - The catalysis over HY and HL was quite different from that over HM.61 63 The further isopropylation of IPN and DIPN isomers was quite rapid in spite of the higher number of bulky isopropyl groups. The yield of IPN had a maximum value during the initial stage of the reaction, and then decreased with reaction time. At longer periods, the product amounts decreased as follows DIPN > IPN > TrIPN. Because the catalytic activities correlate well with the pore surface areas of the zeolite, the isopropylation occurs predominantly inside the pores. These results indicate that HY and HL have enough space for the isopropylation of naphthalene inside their pores. Naphthalene and its alkylates can easily enter into and diffuse out of the pores. 

To be trans to the C-l isopropyl group, the C-3 methyl group must be up. 

Four different types of carbons occur in the aromatic ring and two different types are present in the isopropyl group. The 13C NMR spectrum of isopropylbenzene contains six signals. 

Owing to shorter M-C distances, increased intramolecular contact between the [C5(/-Pr)3H2] anions in the transition metal [M(C5(/-Pr)3H2)2] complexes should decrease the orientational freedom of the isopropyl groups. The melting points of the complexes are in fact higher (>105°C) (Table I). 

The signals at 51.8 and 5 0.9 resemble the pattern for an isopropyl group. The integral ratio of 1 6 supports this assumption. Since the methine (—CH —) proton of the isopropyl group absorbs at a fairly high field, the isopropyl group must be bonded to a carbon atom... 

This obviously minimizes repulsion between the bulky isopropyl groups. The torsion angles between the phenyl rings and the ZrCN2 planes are 89.3°, which is the highest value for any metal benzamidinate complex. 

The metabolic pathways of diazinon are shown in Figure 8.26. Diazinon is mainly hydrolyzed to diethylthiophosphoric acid by cytochrome P450 monooxygenases and esterase (phosphatase). Diazinon is also oxidized by P450s to diazoxon. Microsomal monooxygenases also oxidize diazinon at the isopropyl group. The methyl group on the pyrimidine... 

Note When the DIPT wingtip group in the pincer carbene ligand is substituted for the less sterically cumbersome isopropyl group, the obnormaT coordination mode in the di-pincer carbene complex ofiron(II) is no longer observed. 

Studies aimed at the synthesis of the tetracyclic steroid skeleton from dehydro-abietic acid have centred, in their initial stages, on transformations of the C-13 isopropyl group. The full paper describing the conversion of methyl 12-acetyl-abieta-8,ll,13-trien-18-oate into methyl 13-hydroxypodocarpa-8,ll,13-trien-18-oate by nitrodeacylation and dealkylation reactions, has appeared. Birch reduction of the methyl ether of the phenol afforded the a/5-unsaturated ketone (56) which is a useful synthetic intermediate. Methods for the conversion of podocarpic acid into the a) -unsaturated ketones (57 R = CO2H and CHjOAc) have been investigated reduction of the ester (58 R = C02Me) with lithium in liquid ammonia, which was accompanied by decarboxylation, gave only a... 

Callitrisic acid (4-epidehydroabietic acid) has been synthesized from podo-carpic acid. After insertion of the isopropyl group, the phenolic hydroxy-group... 

The first phosphonia-alkene (155) has been prepared as shown an X-ray crystal structure reveals a twist of 60° around the double bond The diphosphino-diazomethane (156) upon heating in benzene gave (157) by carbene insertion into one of the isopropyl groups. The first diphosphirene (158) has been prepared and... 

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