Perimidin-2-ones

The oxygen atom in perimidin-2-one is replaced using phosphoryl chloride, with formation of 2-chloroperimidine <1981RCR816, 1995AQ151>. 

The quaternary salts 942 are susceptible to oxidative hydroxylation to give l-alkylbenzo[g, ]perimidin-2-ones 943, and the same product can also be obtained by reaction of l-methyl-2-perimidone 944 with benzalacetophenone in PPA <2002RCB139, 2004RJ0895>. 

Potassium cyanate, carbonic and chlorocarbonic esters, phosgene, or urea are used as cyclizing agents in the synthesis of perimidine-2-one 430 (X = X = NR, Y = O) and its derivatives from 1,8-naphthylene-diamines. Naphtho[substituted amino group in position 2 (X = Y = NH or Y = NR) are obtained on interaction of 1,8-naphthylenediamines with bromocyanogen, cyanoamide, 5-methylisothiourea, arylisothiocyanates, or dimethyltri-chloromethylamine. 

Other azines. 1-Substituted perimidines 180 are hydroxylated (KOH, 180C) to form 1-substituted perimidin-2-ones 181 in excellent yields via oxidation of the presumed initial adduct. 

As described in CHEC-11(1996), pyrimidine has one axis of symmetry, about the 2,5-axis, and has three different pairs of bond lengths and four different bond angles <1996CHEC-11(6)93>. 8ymmetry is lost on unequal substitution at the 4-and/or 6-position, and accordingly quinazoline lacks the symmetry of pyrimidine. Perimidine is symmetrical about the 2-position because of proton isomerization (prototropy), but this symmetry is lost on substitution other than at the 2-position. 

Hydroxy, thiol, and amino groups in pyrimidine exist in tautomeric equilibria with their oxo, thioxo, and imino forms. An amino group in an electrophilic position exists predominantly as such, and the compound is named as an amine. Pyrimidines with a hydroxy or thiol group in an electrophilic position are dominated by the oxo or thioxo forms and are named as such, or with -one or -thione suffixes, if these are the principal groups. In the benzenoid 5-position, these derivatives are mainly present in the hydroxy, thiol, or amino forms and are named as such. Similar considerations apply to the nomenclature of quinazolines and perimidines <1996CHEC-II(6)93>. 

Copper-catalyzed reaction of guanidine with l,4-dichloro-9,10-anthracenedione 928 in DMF not only resulted in formation of the targeted 777-benzo[i ]perimidin-7-one ring system, but also resulted in substitution of the second chlorine atom by a dimethylamino group from the DMF solvent to give 929 <2002BMC1025>. 

Monocyclic azines are very weak rr-donors and behave mostly as n-donors on interaction with electrophiles. However, ir-donor character is significantly increased in their benzo-derivatives. For instance, acridine forms with chloranil a highly colored 1 1 molecular complex. Perimidine is one of the strongest heterocyclic ir-donors which gives deeply colored molecular complexes with a variety of organic electron acceptors. On the other hand, the rr-acceptor ability of perimidine is moderate. 

Aromatization of dihydroperimidines 427 to perimidine derivatives 429-431 (X = NR) have been carried out (81UK1559). Benzologs of perimidine-6-ones, or so-called pyrimidinoanthrones (anthrapyrimidines) 441, are well-known dyes. The precursors of these compounds are usually A-(anthraquinonyl-l)-amidines 440, which are obtained from I-aminoanthraquinone 437, as described in the following paragraphs (83M11). 

Valence and prototropic tautomeric reactions are among the most important mechanisms that govern transformations of a broad variety of photochromic organic systems.1,2 Until recently, no examples of photochromic compounds have been reported whose photochromic behavior was due to a combination of these two tautomeric reactions. Such a combination, which is characteristic of ring-chain tautomerism3 has been implemented in the photochromic and thermochromic rearrangements of a novel type of heterocyclic photochromes, derivatives of 2,3-dihydro-2-spiro-4 -(2, 6 -di-iert-butylcyclohexadien-2, 5 -one)perimidine la and its analogs.4 The occurrence of a proton transfer step is in accord with the fact that the AvV -dimethyl derivative of la exhibits no photochromic properties. 

On prolonged passing of air through ethanol or acetonitrile solutions of 1 (R = H) in a quartz photoreactor with an immersed mercury lamp, 2, 3 -dihydro-2 -spiro-4-(2,6-di- ert-butylcyclohexadien-2,5-one)perimidin-4 -one 14 was isolated as the main product of the photooxidation reaction. With the A W -dimethyl derivative of 1, photooxidation results in the formation of the perimidinedione 15.12... 

A mixture of 1,8-naphthalenediamine (3.48 g, 22 mmol), 2-tert-butyl-1,4-naphthoquinone (3.21 g, 15 mmol) and p-toluenesulfonic acid (50 mg) was melted together at 165-170°C for 4 h, cooled to room temperature and dissolved in chloroform (20 ml). The solution was passed through a column (40 x 3.5 cm) filled with A120 3. The column was washed with chloroform-hexane (1 3) and the fraction of orange color collected. After evaporation of the solvent, dark-yellow crystals of 2,3-dihydro-2-spiro-4 -[(4H)-2 -fert-butlnaphthalen-l -one]perimidine (2.06 g, yield 47.8%) were obtained, mp 211-213°C (after recrystallization from methanol and heptane). 

The structural similarity to azoles and the resemblance of many physicochemical properties allow one to consider peri-codensed NH-heterocycIes of the perimidine type (236) as analogues of azolo heterocycles (85KGS867). Under the action of MSH, perimidine and its substituted derivatives give the quaternary salt 237 in good yield (80KGS93 83CPB1378). One of these salts was converted to l-methyl-3-amino-2,3-... 

Perimidine is one of the few azines in which the lone pair of a pyrrole-like nitrogen participates in the 7t-system of the molecule. Perimidine is therefore a 14-7t electron system, isoelectronic with the phenalenyl anion. An important consequence of this interaction is a transfer of electron density from the heterocyclic ring into the naphthalene moiety. Therefore perimidine exhibits simultaneously the characteristics of both 7r-deficient and 7t-excessive systems <87H(26)I029>. 

X-ray structure data for 2-(2-methoxyphenyl)perimidine shows the compound to be roughly planar ((12a) and (12b) in Figure 3). The naphthalene moiety presents a similar pattern of bond distances and angles as in naphthalene <93MI 602-0l>. X-ray structure data for 1-methyl-l//-per-imidin-2(3F0-one and its 1,3-dimethyl derivative show lack of planarity with the methyl groups eclipsed with the C=0 group (94HCA121). 

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