N-(17-Acyloxy-acyl)-glutamines: novel surfactants from oral secretions of lepidopteran larvae

N-(17-Acyloxy-acyl)-glutamine conjugates such as N-(17-linolenoyloxy-linolenoyl)-glutamine (6), N-(17-linolenoyloxy-linoleoyl)-glutamine (7), N-(17-linoleoyloxy-linolenoyl)-glutamine (8), and N-(17-linoleoyloxy-linoleoyl)-glutamine (9) were identified as novel surfactants in the oral secretion of several lepidopteran larvae (S. exigua, S. littoralis, S. frugiperda, and H. virescens) by LC-MS/MS and chemical degradation. Authentic reference compounds were synthesized via a dissymmetric bis-Wittig approach and confirmed the assigned structures.     

合成固载希夫碱配合物作为配体交换材料

Two new sporopollenin-immobilized Schiff bases, S-[N-(2-aminoetil) salicylaldiimino] and S-[N-(2-aminoetil) benzaldiimino], and their cobalt (Ⅲ) and nickel (Ⅱ) complexes, S-[N-(2-aminoetil) benzaldiimino] aquatriacetato cobalt (Ⅲ), S-[N-(2-aminoetil) salicylaldiimino] aquadiacetato cobalt (Ⅲ), S-[N-(2-aminoetil) benzaldiimino] diacetato nickel (Ⅱ), and S-[N-(2-aminoetil) salicylaldiimino] diacetato nickel (Ⅱ), were synthesized onto a chemically modified sporopollenin with ethylenediamine. The immobilized ligands and their metal complexes were characterized by thermal analysis and spectroscopic techniques such as infrared, ultraviolet-visible, and atomic absorption spectrometry. Immobilized Schiff base metal complexes, S-[N-(2-aminoetil) benzaldiimino] aquatriacetato cobalt (Ⅲ) and S-[N-(2-aminoetil) salicylaldiimino] aquadiacetato cobalt (Ⅲ), were used as ligand exchanger media to investigate ligand adsorption behavior of methylene blue (MB) with column technique. The result shows that the chelation of methylene blue with S-[N-(2-aminoetil) salicylaldiimino] aquadiacetato cobalt (Ⅲ) complex increases ligand adsorption capacity.     

Novel approach to aminocarboranes by mild amidation of selected iodo-carboranes

A mild protocol for the palladium-catalyzed Buchwald-Hartwig amidation of icosahedral carboranes is described. Employing 2-dicyclohexylphosphino-2'-(N,N-dimethylamino)biphenyl (1) as a ligand and K(3)PO(4) as a base, benzamide, trifluoroacetamide, acetamide, and formamide were coupled to a series of mono- and di-iodo carboranes furnishing the respective carborane derivatives in good to excellent yields. Subsequent base-mediated saponification of the trifluoroacetamide derivatives was shown to provide the free aminocarboranes. The structures of N-(1,7-dicarba-closo-dodecaboran-9-yl)benzamide (8a), N-(1,7-dicarba-closo-dodecaboran-9-yl)trifluoroacetamide (8b), N-(1,12-dicarba-closo-dodecaboran-2-yl)benzamide (10a), N-(1,2-dicarba-closo-dodecaboran-9-yl)benzamide (12a), N-(1,2-dicarba-closo-dodecaboran-9-yl)acetamide (12c), N-(1,2-dicarba-closo-dodecaboran-9-yl)formamide (12d), N-(1,2-dicarba-closo-dodecaboran-3-yl)benzamide (13a), N,N'-(1,7-dicarba-closo-dodecaboran-9,10-diyl)dibenzamide (15a), and N,N'-(1,7-dicarba-closo-dodecaboran-9,10-diyl)bis(trifluoroacetamide) (15b) have been established through X-ray single-crystal diffraction studies.     

Synthesis, characterization and colour determination using CIELAB colour space of stilbene dyes

The synthesis of six new symmetrical disazo direct dyes containing 4,4′-diaminostilbene-2,2′-disulphonic acid as middle component and N-(2-chlorophenyl)-2-hydroxybenzamide, N-(3-chlorophenyl)-2-hydroxybenzamide, N-(4-chlorophenyl)-2-hydroxybenzamide, N-(2-bromophenyl)-2-hydroxybenzamide, N-(3-bromophenyl)-2-hydroxybenzamide, N-(4-bromophenyl)-2-hydroxybenzamide as coupling components is presented. The synthesized dyes were analyzed by thin layer chromatography, electronic spectra and HPLC technique. Their structures were elucidated by FT/IR and 13C-NMR spectroscopy. The CIELAB (1976) colour space was used in all the colour measurements for the six disazo stilbene dyes under the CIE recommended illuminants: D65 (natural day light), A (tungsten light), F2 (fluorescent light) and the standard 10° observer, respectively. The colour differences: ΔEab* and ΔECMC were calculated against one standard. The results reveal a good colouring power of the new azo-stilbene dyes.     

Methoxymethyl (MOM) group nitrogen protection of pyrimidines bearing C-6 acyclic side-chains

Novel N-methoxymethylated (MOM) pyrimidine (4-13) and pyrimidine-2,4-diones (15-17) nucleoside mimetics in which an isobutyl side-chain is attached at the C-6 position of the pyrimidine moiety were synthesized. Synthetic methods via O-persilylated or N-anionic uracil derivatives have been evaluated for the synthesis of N-1- and/or N-3-MOM pyrimidine derivatives with C-6 acyclic side-chains. A synthetic approach using an activated N-anionic pyrimidine derivative afforded the desired N,N-1,3-diMOM and N-1-MOM pyrimidines 4 and 5 in good yield. Introduction of fluorine into the side-chain was performed with DAST as the fluorinating reagent to give a N,N-1,3-diMOM pyrimidine 13 with a 1-fluoro-3-hydroxyisobutyl moiety at C-6. Conformational study of the monotritylated N-1-MOM pyrimidine 12 by the use of the NOE experiments revealed the predominant conformation of the compound to be one where the hydroxymethyl group in the C-6 side-chain is close to the N-1-MOM moiety, while the OMTr is in proximity to the CH(3)-5 group. Contrary to this no NOE enhancements between the N-1-MOM group and hydroxymethyl or fluoromethyl protons in 13 were observed, which suggested a nonrestricted rotation along the C-6 side-chain. Fluorinated N,N-1,3-diMOM pyrimidine 13 emerged as a model compound for development of tracer molecules for non-invasive imaging of gene expression using positron emission tomography (PET).     

N-2-氯苄基苯甲酰胺的固相合成及其晶体结构分析

N-2-氯苄基苯甲酰胺采用固相法制备.聚苯乙烯磺酰氯(1)在吡啶存在下与2-氯苄胺反应得到N-2-氯苄基磺酰胺树脂(2),进一步在吡啶催化下用苯甲酰氯进行酰化得到N-2-氯苄基-N-苯甲酰基磺酰胺树脂(3).用TiCl₄/Zn/THF试剂处理,从树脂3上解脱得到产物N-2-氯苄基苯甲酰胺(4),产率92%.N-2-氯苄基苯甲酰胺的晶体属于单斜晶系,P2₁空间群,晶胞参数:a=0.7149(3)_nm,b=0.8772(4)_nm,c=0.9704(4)_nm;β=95.172(7)°;晶体结构中存在两种分子间氢键相互作用.     

The electrochemical fluorination of N-(ω-chloroalkyl)pipecolines and N-(ω-chloroalkyl)hexamethyleneimines

Electrochemical fluorinations of six kinds of N-(ω-chloroalkyl)pipecolines [N-(2-chloroethyl)-2-, N-(3-chloropropyl)-2-, N-(2-chloroethyl)-3-, N-(3-chloropropyl)-3-, N-(2-chloroethyl)4- and N-(3-chloropropyl)-4-pipecolines] and two kinds of N-(ω- chloroalkyl)-substituted hexamethyleneimines [N-(2-chloroethyl)- and N-(3-chloropropyl)hexamethyleneimines] were conducted. From these starting materials, corresponding chlorine-retained fully fluorinated amines together with ring isomerized products were formed in yields of 7.6～14.8% from the former and 5.4～5.5% from the latter, respectively. New chloropolyfluoroamines obtained in the present investigation have been isolated and characterized by spectroscopic (infrared, ¹⁹F nmr and mass) and elemental analysis.     

Protonated adenine: Tautomers,solvated clusters,and dissociation mechanisms

Ab initio and density functional theory calculations at the B3-MP2 and CCSD(T)/6-311 + G(3df,2p) levels of theory are reported that address the protonation of adenine in the gas phase, water clusters, and bulk aqueous solution. The calculations point to N-1-protonated adenine (1+) as the thermodynamically most stable cationic tautomer in the gas phase, water clusters, and bulk solution. This strongly indicates that electrospray ionization of adenine solutions produces tautomer 1+ with a specificity calculated as 97-90% in the 298-473 K temperature range. The mechanisms for elimination of hydrogen atoms and ammonia from 1+ have also been studied computationally. Ion 1+ is calculated to undergo fast migrations of protons among positions N-1, C-2, N-3, N-10, N-7, and C-8 that result in an exchange of five hydrogens before loss of a hydrogen atom forming adenine cation radical at 415 kJ mol(-1) dissociation threshold energy. The elimination of ammonia is found to be substantially endothermic requiring 376-380 kJ mol(-1) at the dissociation threshold and depending on the dissociation pathway. The overall dissociation is slowed by the involvement of ion-molecule complexes along the dissociation pathways. The competing isomerization of 1+ proceeds by a sequence of ring opening, internal rotations, imine flipping, ring closures, and proton migrations to effectively exchange the N-1 and N-10 atoms in 1+, so that either can be eliminated as ammonia. This mechanism explains the previous N-1/N-10 exchange upon collision-induced dissociation of protonated adenine.     

Cyclization of the substituted <Emphasis Type="Italic">N</Emphasis>-(<Emphasis Type="Italic">Ortho</Emphasis>-cyclopropylphenyl)-<Emphasis Type="Italic">N′</Emphasis>-aryl ureas and thioureas in the gas phase and solution

Electron ionization (EI), chemical ionization (CI), tandem mass spectrometry, high-resolution measurements, and labeling studies as well as quantum chemical calculations were used to understand the behavior of the molecular radical cations (EI) and protonated molecules (CI) of substituted N-(ortho-cyclopropylphenyl)-N'-aryl ureas and N-(ortho-cyclopropylphenyl)-N'-aryl thioureas in a mass spectrometer. Fragmentation schemes and possible mechanisms of primary isomerization were proposed. According to the fragmentation pattern, formation of the corresponding benzoxazines and benzothiazines was considered as the major process of isomerization of the original M(+.) and MH(+), although some portions of these ions definitely transformed into other structures. The treatment of N-(ortho-cyclopropylphenyl)-N'-phenyl urea and N-(ortho-cyclopropylphenyl)-N'-phenylthiourea in solution with strong acids formed predicted 4-ethyl-N-phenyl-4H-3,1-benzoxazin-2-amin and 4-ethyl-N-phenyl-4H-3,1-benzothiazin-2-amine as principal products.     

Improvement of physicochemical properties of N-4472. Part III. VC/N-4472 complex formation and self-association in aqueous solution

To improve the aqueous solubility of a poorly water-soluble drug, N-[2-(3,5-di-tert-butyl-4-hydroxyphenethyl)-4,6-difluorophenyl]-N'-[4-(N-benzylpiperidyl)]urea (N-4472), organic acid/N-4472 evaporates were prepared by using succinic acid, L-tartaric acid, citric acid and L-ascorbic acid (VC). Among these evaporates, only the VC/N-4472 evaporate at a molar ratio of more than 2 (VC/N-4472) formed stable colloidal particles (with a mean particle size 相似文献   

Exceptionally Persistent Nitrogen-Centered Free Radicals. Syntheses, ESR Spectra, Isolation, and X-ray Crystallographic Structures of N-(Arylthio)-2-tert-butyl-4,6-diarylphenylaminyl and N-(Arylthio)-4-tert-butyl-2,6-diarylphenylaminyl Radicals(1)

The preparation, ESR spectra, isolation, and X-ray crystallographic structure of N-(arylthio)-2-tert-butyl-4,6-diarylphenylaminyls (1) and N-(arylthio)-4-tert-butyl-2,6-diarylphenylaminyls (2) are described. The aminyls are generated by PbO(2) oxidation of N-(arylthio)-2-tert-butyl-4,6-diarylanilines and N-(arylthio)-4-tert-butyl-2,6-diarylanilines. The kinetic ESR study shows that the aminyls are quite persistent, even in the presence of oxygen, and exist in the individual radical forms. Among the seventeen aminyls prepared, N-[(4-nitrophenyl)thio]-2-tert-butyl-4,6-diphenylphenylaminyl (1b), N-[(4-nitrophenyl)thio]-2-tert-butyl-4,6-bis(4-chlorophenyl)phenylaminyl (1f), N-[(4-nitrophenyl)thio]-4-tert-butyl-2,6-diphenylphenylaminyl (2b), N-[(4-nitrophenyl)thio]-4-tert-butyl-2,6-bis(4-chlorophenyl)phenylaminyl (2h), and N-[(3,5-dichlorophenyl)thio]-4-tert-butyl-2,6-bis(4-chlorophenyl)phenylaminyl (2j) are isolated as radical crystals. The crystallographic structures of 1b and 2b are determined by the X-ray crystallographic analyses. Aminyls 1 and 2 give similar ESR spectra consisting of 1:1:1 triplets with the a(N) values of 0.921-0.948 mT. Deuteration of the phenyl groups on the anilino benzene ring gives rise to a further splitting of the nitrogen 1:1:1 triplet by the anilino meta (0.126-0.138) and phenylthiyl ortho and para protons (0.077-0.096 mT). Upon recording at high gain, one of the partly deuterated aminyls gives satellite lines due to (33)S isotopes at natural abundance from which a(33)(S) is determined to be 0.51 mT. The ESR parameters for 1 and 2 are compared with those for structurally close N-(arylthio)-2,4,6-triarylphenylaminyl and N-(arylthio)-2,4,6-tri-tert-butylphenylaminyl.     

Backbone modifications of aromatic peptide nucleic acid (APNA ) monomers and their hybridization properties with DNA and RNA

Aromatic peptide nucleic acid (APNA) monomers containing N-(2-aminobenzyl)-glycine, N-(2-aminobenzyl)-(R)- or -(S)-alanine, and N-(2-aminobenzyl)-beta-alanine moieties as part of their backbone were synthesized. These novel analogues were incorporated as a single "point mutation" in PNA hexamers, and their physicochemical properties were investigated by UV thermal denaturation and CD experiments. Destabilization in triplex formation between the PNA-APNA chimeras and complementary DNA or RNA oligomers was observed, as compared to the PNA control. The APNA monomer composed of the N-(2-aminobenzyl)-glycine backbone led to the smallest decrease in the thermal stability of the triplexes formed with DNA and RNA, while maintaining selectivity for base-pairing recognition. Since the PNA-APNA chimeras are more lipophilic than the corresponding PNA homopolymers, these oligomers may also exhibit better cell membrane permeability properties.     

Synthesis and spectroscopic studies of novel mononuclear and binuclear ruthenium(III) complexes with bidentate and tridentate acyclic hydrazones

Nine novel acyclic hydrazone ligands, FINH?=?N-(furylidene)-N′-isonicotinoylhydrazine, FNH?=?N-(furylidene)-N′-nicotinoylhydrazine, PINH?=?N-(pyrienylidene)-N′-isonicotinoylhydrazine, PNH?=?N-(pyrienylidene)-N′-nicotinoylhydrazine, TINH?=?N-(thienylidene)-N′-isonicotinoylhydrazine, TNH?=?N-(thienylidene)-N′-nicotinoylhydrazine, FSH?=?N-(furylidene)-N′-salicyloylhydrazine, PSH?=?N-(pyrienylidene)-N′-salicyloylhydrazine and TSH?=?N-(thienylidene)-N′-salicyloylhydrazine, have been synthesized. Their corresponding mononuclear and binuclear ruthenium(III) complexes have been prepared by the reaction of the ligand with RuCl₃·3H₂O in 1?:?2 and 2?:?2 molar ratio and are characterized by elemental analyses, thermogravimetric analyses (TGA and DTG), IR, electronic, magnetic susceptibility and electrical conductance measurements. Electronic spectra and magnetic susceptibility measurements of the solid complexes (both mono- and binuclear) indicate an octahedral geometry around ruthenium(III). Particular emphasis is given to the binuclear complexes in which FSH, PSH and TSH behave as tridentate ligands and chloride bridges the Ru(III) ions. Conductance measurements show the mononuclear complexes are electrolytic and binuclear complexes are of non-electrolytic. The fungicidal activities of the ligands and metal complexes against Fusarium oxysporium and Aspergillus niger are described.     

Synthesis of a novel fluorescent probe and investigation on its interaction with nucleic acid and analytical application

A novel fluorescent probe N-(N-(2-(4-morpholinyl)ethyl)-4-acridinecarboxamide)-alpha-alanine (N-(N-(ME)-4-ACA)-alpha-ALA) was synthesized. The structure was characterized by 1H NMR, MS, elemental analysis, fluorescent and ultraviolet spectra. This new compound exhibited high binding affinity to DNA, intense fluorescence and high water solubility. Experiment indicated that the fluorescent intensity was quenched when DNA was added. A method for DNA determination based on the quenching fluorescence (lambda(ex)=258nm, lambda(em)=451nm) of N-(N-(ME)-4-ACA)-alpha-ALA was established. Under optimal conditions (pH 7.2, CN-(N-(ME)-4-ACA)-alpha-ALA)=3 x 10(-6) mol L(-1)), the linear range is 0.1-4.0 microg mL(-1) for both fish semen (fsDNA) and calf thymus DNA (ct-DNA). The corresponding determination limits are 4.6 ng mL(-1) for fsDNA and 5.1 ng mL(-1) for ct-DNA, respectively. The relative standard deviation is 1.0%. Thus this compound can be used as a DNA fluorescent probe. The experiments proved that the interaction mode between N-(N-(ME)-4-ACA)-alpha-ALA and DNA was groove binding. The modified Rosenthal's graphical method gave the binding constant of 1.0 x 10(6) L mol(-1) and a binding size of 0.31 base pairs per bound drug molecule.     

Ring opening photoreactions of cytosine and uracil with ethylamine

The photochemical reactions of cytosine (Cyt) and uracil (Ura) with ethylamine, an analog of the side chain of the amino acid lysine, have been studied. After irradiation of Cyt in aqueous ethylamine at lambda = 254 nm, N-(N'-ethylcarbamoyl)-3-aminoacrylamidine (Ia) and N-(N'-ethylcarbamoyl)-3-ethylaminoacrylamidine (Ib) were isolated as products, while irradiation of Ura gave N-(N'-ethylcarbamoyl)-3-aminoacrylamide (IIa) and N-(N'-ethylcarbamoyl)-3-ethylaminoacrylamide (IIb) as products. Studies in which Ia and IIa were incubated with ethylamine at various pH values indicate that Ib and IIb are secondary products produced via thermal reactions of Ia and IIa with ethylamine. Heating of Ia and Ib leads to ring closure with the resultant formation of 1-ethylcytosine; small amounts of 1-ethyluracil are also produced. Heating of IIa and IIb produces 1-ethyluracil as the sole product. Spectroscopic properties were determined for each of these opened ring products, as well as for N-(N'-ethylcarbamoyl)-3-amino-2-methylacrylamidine (III) and N-(N'-ethylcarbamoyl)-3-amino-2-methylacrylamide (IV). Quantum yield measurements showed that Ia was formed with a phi of 1.6 x 10(-4) at pH 9.8, while phi for formation of IIa was 7.2 x 10(-4) at pH 11.5. A profile of the relative quantum yield for formation of Ia, determined as a function of pH, showed that the maximum quantum yield occurs at around pH 9.5; the analogous profile for IIa shows a maximum quantum yield at pH 11.3 and above. Acetone sensitization does not produce Ia in the Cyt-ethylamine system, which indicates that the known triplet state of Cyt is not involved in reactions leading to this opened ring product.     

A study of furan compounds

[N-(2-Furoyl)-, N-(5-methyl-2-furoyl)-, N-(5-chloro-2-furoyl)-, N-(5-bromo-2-furoyl)-, N-(5-iodo-2-furoyl)-, N-(5-nitro-2-furoyl)-, and N-(tetrahydro-2-furoyl) ureas were obtained by acylation of urea with the corresponding acid chlorides.For part XXXIV, see [23].     

Photoaddition of N-substituted piperazines to C60: an efficient approach to the synthesis of water-soluble fullerene derivatives

An oxidative radical photoaddition of mono N-substituted piperazines to [60]fullerene was systematically investigated. Reactions of C60 with piperazines bearing bulky electron-withdrawing groups (2-pyridyl, 2-pyrimidinyl) were found to be the most selective and yielded C60(amine)4O as major products along with small amounts of C60(amine)2. In contrast, interactions of fullerene with N-methylpiperazine and N-(tert-butoxycarbonyl)piperazine were found to have low selectivity due to different side reactions. Tetraaminofullerene derivative C60(N-(2-pyridyl)piperazine)4O was found to react readily with organic and inorganic acids to yield highly water-soluble salts (solubility approximately 150 mg mL(-1)). In contrast, C60(N-(2-pyrimidinyl)piperazine)4O undergoes hydrolysis under the same conditions and results in a complex mixture of compounds with an average composition of C60(N-(2-pyrimidinyl)piperazine)2(OH)2O. Radical photoaddition of N-(2-pyridyl)piperazine to fullerene derivatives can be used as a facile route for their transformation into water-soluble compounds. Two model fullerene cycloadducts (a methanofullerene and a pyrrolidinofullerene) were easily converted into mixtures of regioisomers of A=C60(N-(2-pyridyl)piperazine)4O (A=cyclic addend) that give highly water-soluble salts under acid treatment.     

Theoretical study on the assembly and stabilization of a magic cluster Al4N-

We report the first attempt to assemble the magic cluster Al4N- on the basis of the density functional theory calculations on a series of pi-stacked dimers (Al4N-)2, sandwich-like compounds [D(Al4N)M]q- (where D = Al4N-, Cp-(C5H5-); M = Li, Na, K, Be, Mg, Ca) and extended compounds (Cp-)m(Li+)n(Al4N-)o (where m, n, and o are integers). For the six metals, the magic Al4N- can only be assembled and grow up in our newly proposed "hetero-decked sandwich" scheme (e.g., [CpM(Al4N)]q-) so as to avoid cluster fusion. The ground-state hetero-decked sandwich species (Cp-)(M)q+(Al4N)- (M = Li, Na, K, q = 1; M = Be, Mg, Ca, q = 2) and the extended sandwich species (Cp-)m(Li+)n(Al4N-)o are mainly ionically bonded, cluster-assembled "polyatomic molecules", grown from the combination of Cp-, M-atoms, and Al4N-. As a prototype for ionic bonding involving intact Al4N- subunits, [CpM(Al4N)]q- may be a stepping stone toward forming ionic, cluster-assembled AlN compounds.     

Synthesis of N-Substituted 3-Aminothiazolidin-4-ones Containing Hetaryl Fragments

Condensation of the N-(3,5-dichloropyridyl-2)- and N-(benzothiazolyl-2-thioacetyl)hydrazones of carbonyl compounds with thioglycolic acid gave the 3-(3,5-dichloropyridyl-2)amino- and 3-[N-(benzothiazolyl-2-thioacetyl)amino]-2-R¹-2-R²-thiazolidin-4-ones. Reaction of 1-(benzothiazolyl-2-thioacetyl)-4-R-thiosemicarbazides with chloroacetic acid in the presence of sodium acetate gave the 2-[N-(benzothiazolyl-2-thioacetyl)hydrazono]-3-R-thiazolidin-4-ones. It was found that the N-(benzothiazolyl-2-thioacetyl)hydrazones, both in the solid state and in solution, exist in the form of an equilibrium mixture of the EZ'- and EE'-isomers as a result of hindered rotation around the amide N-CO bond.     

Promising Ultraviolet Absorbers—Novel Guanine Analogs Having Significantly Improved Ultraviolet Absorption Capacity and Dissipating the Energy of Absorbed Photons by Nonradiative Decay Mechanism

Structural properties of nucleobase underlie their ultrafast excited-state dynamics and low fluorescence quantum yields, which cause effectively nonradiative decay process and render them like sunscreens. Thus, eight guanine analogs[N-2-(2'-nitrobenzoyl)-guanine, N-2-(3'-nitrobenzoyl)-guanine, N-2-(4'-nitrobenzoyl)-guanine, N-2-(2'-hydroxybenzoyl)-guanine, N-2-(4'-methoxylbenzoyl)-guanine, N-2-(4'-chloricbenzoyl)-guanine, N-2-(4'- methylicbenzoyl)- guanine and N-2-(3',5'-dinitrobenzoyl)-guanine] with different substituted benzoyls, except N-2-(4'-chloricbenzoyl)-guanine, were newly synthesized. In contrast with guanine, they exhibit wider ultraviolet absorbent range, higher molar extinction coefficient and lower fluorescence intensity.