FORM 2
The Patent Act 1970,
(39 of 1970)
&
The Patent rule 2003 Complete Specification
(See Section 10 and Rule 13)
1. TITLE OF THE INVENTION
"PROCESS FOR THE PREPARATION OF NOVEL AZO PIGMENTS OF 2-AMINO ACRIDONE AND ITS DERIVATIVES"
2. APPLICANT(S)
(a) NAME : QHARDA CHEMICALS LTD
(b) NATIONALITY: INDIAN
(c) ADDRESS: B-27/29, MIDC, PHASE 1, DOMBIVLI.
DIST. THANE, PIN 421 203 MAHARASHTRA INDIA
3. PREAMBLE OF THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.

Field of Invention
The present invention relates to a process for preparation of novel organic azo pigments derived from 2-amino acridone (1) and its derivatives preferably N-alkylated derivatives. The methodology involves diazotization of 2-amino acridone and its derivatives in the first stage followed by coupling of those diazo salts with different coupling components as described below in the second stage. The preferred azo pigments (2) produced by this process exhibit yellow shades of varying hues,




STRUCTURE (I)
R' =HorAlkyl, C,-C4
R = H, Aceto acetyl
Structure (II): R = H, C,-C4 alkyl

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Background of the invention:
Process for the preparation of azo pigments derived from 2-amino acridone and its N-alkylated derivatives is described with the application of the said pigments
at different literatures.
US 2,694,713 reported stray organic pigment and dyestuff molecules of azo family obtained by coupling diazotised 2-amino acridone on BON acid derivatives.
US 2,647,901 describe preparation and applications of 1-(tertiary-amino alkylamino) acridones with yellow to orange shade and having better dyeing tinting properties.
US 3,932,414 disclosed diazo pigments prepared from acridine having different substituents like halogen, nitro, cyano, methyl, alkoxy, aminocarbonyl, alkylcarbonylamino, benzoylamino, phenylaminocarbonyl, alkylamino or phenylamino and their use in pigmenting synthetic plastics and resins and paper and as colorants in surface coating media such as paints, lacquers and printing inks.
US 4,033,965 describe a nitro acridine dyes having disperse property which contains no water solubilizing groups.
US 4,286,998 describes a solid solution of a quinacridonequinone with a stabilizer selected from the group consisting of 2-anilino acridone, 5,6,7,8 tetrahydro-2-anilinoacidone, 6-anilinoquinolone and 2-amino acridone of improved light fastness is provided which displays improved dispersibility while still maintaining a high degree of transparency in automotive finishes when post treated with a surfactant.
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Among the various known quinacridone derivatives are the quinacridonequinone. Quinacridonequinones have been described in the literature as having utility as pigments because of their intense yellow colour and low solubility in organic media. As a practical matter, however, compositions pigmented with
Quinacridonequinones have proven to have extremely poor light fastness as compared to those pigmented with quinacridone or other quinacridone derivatives.
While it has been disclosed (U.S. pat. No. 3,160,510) that quinacridonequinone could be used as one component of a solid solution of two or more quinacridone derivatives, such compositions have marked limitations since the ingredients are colored compounds which produce a red colour in the final composition.
More recently colorless stabilizers, such as N,N-di phenyl-p-phenylene diamine (U.S. Pat. No. 3,341,345) and 6,13-hihydroquinacridone (U.S. Pat. No. 3,748,162), have been used in solid solution with quinacridonequinone. US 6,007,691 describe the methods and kits for conveniently diagnosing various physiological conditions that produce altered levels of specific carbohydrates, known as diagnostic carbohydrates. Measurement of levels of diagnostic carbohydrates is performed by 2-amino acridone being used in fluorophore assisted carbohydrate electrophoresis. Physiological conditions of particular interest that may be ascertained by the subject invention include carbohydrate metabolism diseases, autoimmune diseases, neoplasia, toxic chemical exposure and microbial infections. Fluorophore assisted carbohydrate electrophoresis diagnosis may be applied to various patient specimens, including blood, urine and skin.
EP 0763580 describes manufacturing process of various dyes based on acridone. Acridone-anthraquinone series organic dyes and have been used as pigment dispersing agent for improving the adaptability for use of water based printing ink or water paint.
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WO 0238,549 describes heteroanellated aminophenols. Furthermore, the invention provides azo compounds and azomethine compounds. The invention describes the use of the said compounds for the mass coloration of substrates,
as colorant in electrophotographic toners and developers, in powder and powder
coating materials, in ink-jet inks and in cosmetic compositions.
JP 59-91150 & JP 59-98058 describe manufacture of di hydro acridone derivatives, as an intermediate for quinacridone class of pigments. JP 59-113061 describes dark, purple colored polyacridone derivatives (both linear and angular) useful as organic pigments.
None of the above compounds address the acetoacetylation product of 2-aminoacridone and the process thereof. It is observed that the above product of 2-amino acridone if used for the preparation of azo pigments result good colour index and show the high shelf life of the pigments and lasting for a longer period. It is thus an object for the present invention to provide a novel process for the preparation of azo pigments derived from 2-amino acridone and its N-alkylated derivatives, which no longer suffers from the above drawbacks and is simple to carry in to effect industrially. It is the further object to obtain the end products in good yield and to a high degree of purity.
OBJECT OF INVENTION
It is an object of invention to provide novel organic azo pigments having yellow
shades of varying hues.
Another object of this invention is to provide a process for preparing novel azo
pigments derived from 2-aminoacridone as an important building block.
Still another object of this invention is to provide yellow pigments having superior
thermal stability, weatherability, migration resistance and resistance to solvents.
Still another object of this invention is to create a yellow to orange shade and
having better dyeing, tinting properties.
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The other objects and features of the present invention will become apparent from the following description.
STATEMENT OF INVENTION
Process for preparation of organic azo pigment derived from 2-aminoacridone and N-alkylated derivatives comprises of diazotization of the said compounds followed by coupling with various coupling components such as herein described offer quality azo pigments.
DESCRIPTION OF THE INVENTION
According to the invention, the organic azo pigments are produced from 2-aminoacridone and/or its N-alkyl analogue utilizing the amine function for preparation of diazonium salts or preparation of coupling component with di ketene or acetoacetic ester. The diazonium salts derived from 2-aminoacridone or its N-alkyl derivative coupled on acetoacetyl derivative of 2-amino acridone derivative or 5-amino benzimidazolone and their anilides derived from BON acid. Acetoacetyl derivative is produced by reacting methyl or ethyl acetoacetate with Amine in solvent like chlorinated aromatic hydrocarbon at reflux in presence of strong base. The product obtained was then isolated by filtration.
Synthesis of di azo pigment is carried out by di azo coupling of 2-amino acridone derivatives with the coupling component as described above by the conventional process. Suitable temperature, pH and duration of reaction are set up according to the nature of reactants used in the process of preparation. The pigments, which are formed, filtered under hot condition and washed with water and further treated with suitable organic solvent for obtaining the purity of the end product. Thus with this novel process the organic azo pigment is produced in good yield and high scale of purity. The invention is illustrated below by the following example.
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Example:
Synthesis of Diazo pigment bv di azo coupling of 2-amino acridone derivative (I.
R = H & R' = H) on 5-(N-aceto acetyl) amino 2-benzimidazolone.
Diazotization of 2-amino acridone derivative (I, R = H & R' = H, alkyl C1-C4):
Suspended 0.1 m 2-amino acridone (I, R = H & R' = H) into 275 mM N HCI.
Cooled entire mixture to 0-5°c. To this mixture added aq. solution of 7.3 gms
(0.105 m) NaN02 over 30-min. Stirred at 0-5°c for 1 hr. the excess NaN02 is
destroyed by known technique. This results into component A.
Coupler B: Separately prepared a solution of 25 gms of 5-(N-aceto acetyl) amino
2-benzimidazolone (0.1 m) and 24 gms of 33% NaOH in 200-ml water at 20°c.
Filtered this solution through a suitable filtering media.
Also separately prepared a solution of 12 gms acetic acid in 200-ml water
containing suitable dispersing agent. To this solution added above coupler B
solution at 20°c over 15-20 min, maintaining the suitable pH, preferably at pH 5-
6,stirred further for 20 min.
To this solution added diazo mass prepared as above at 15-20°c over 3 hrs
maintaining pH between 3-7. Stirred for 1 hr and raised the temperature to 90°c
and maintained for 4 hrs. The pigment thus formed filtered hot and washed with
water and further treated with suitable organic solvents.
Different embodiment of the invention is possible to achieve the best method of
performance and to obtain the product as stated above to meet the object of the
invention. It will be understood that skilled persons with many modifications,
variations and adaptations may carry out the invention into practice without
departing from its spirit or exceeding the scope of claims in describing the
invention for the purpose of illustration.
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We Claim,
1. Process for the preparation of organic azo pigment (2) derived from 2-
aminoacridone (1) and N-alkylated derivatives comprises of diazotization of
the said compounds followed by coupling with various coupling components such as herein described offer quality azo pigments wherein R' is either H or C1-C4 alkyl.
2. Process as claimed in claim 1 wherein the coupling component is acetoacetylated moiety or Napthol and/or with various aromatic, heteroaromatic or heterocyclic substituents.
3. Process as claimed in claim 1 wherein the coupling is carried out at wide range of pH from 3-7 or more preferably at 5-6.
4. Process as claimed in claim 1 where the acetoacetylated product is reprecipittated into aqueous solution as a finely dispersed solids by neutralization of its sodium salt in presence of dispersing agents.
5. Process claimed in claim 1 wherein the coupling is carried out at temperature ranging from 10°c to 40°c or more preferably at 10°c to 20°c.
6. Process as claimed in claim 1 wherein the reaction mixture is digested at 70°c to 100°c for 3-4 hours after the process of coupling to obtain good yield of the end product.
5. Process as claimed in claim 1 wherein the whole coupling reaction is carried out under stirring condition to allow homogenous mixture and to avoid any undesirable product.
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8. Process as claimed in claim 1 wherein the product is finally purified by treatment with suitable organic solvents).
9. Process as claimed in preceding claims substantially as herein described.

Abstract:
The present invention describes the preparation of novel azo pigments,
represented by structure (II) from 2-amino acridone derivatives, prepared by
STRUCTURE (I)
R" =HorAlkyl(C,-C4)
R = H, Aceto acetyl
known methods and as described by structure (I).


Structure (II): R1 = H, C,-C4 alkyl
'A' in above structure (II) represents various coupling components described herein.