On the Fluorescence Reaction of Pharmaceutically Important 13-Diamines and o-Aminobenzenesulfonamides with Homophthalaldehyde.

Notes
On the Fluorescence Reaction of Pharmaceutically Important
1,3-Diaminesand o-Aminobenzenesulfonamides with
Homophthalaldehyde
Reinhard Troschutz" and Oliver Heinemann
Institut fur Pharmdzie und Lebensmittelchemie der Friedrich-Alexander-UniversitatErlangen-Niirnberg, Schuhstr. 19, D-91052 Erlangen
Key Words:fluorescence; homophthalaldehyde; primary 1,3-diamines; o-aminobenzenesulfonamides
Summary
On treatment with pharmaceuticallyimportant primary 1,3-diamines 2 and 8 as well a.o-aminobenzenesulfonamides13-15. homophthalaldehyde (1) yields the intensely blue fluorescent,
heteroanellatedisoquinolines 5 and 9, as well as moderately fluorescent isoquinobenzothiadiazines1 6 1 8 .
proton 8-H and the olefinic proton 6-H is noticed. This
excludes the formation of the isoquino[2,1 -a]quinazoline 6.
The reaction probably starts with the formation of an N,Nacetal 3, which eliminates one equivalent of water intramolecularly to yield the isoquino[ 1,2-b]quinazoline 5 via the
dihydro-derivative 4.
Oxazepam
I'3
Introduction
1) NaOHIEtOH, A
2) NaOHco,c,Ethyiene glycol, A
Phthalaldehyde is reacted with 1,5-N-bisnucleophiles, i.e.
primary I ,3-diamines, o-aminobenzamides, and o-aminobenzenesulfonamides, which are generated by hydrolysis of
drugs, to provide moderate to intensely fluorescing products
The reaction of 1 with primary 1,3-diamines, generated
from Oxazepam and Lorazepam, established the basis for a
highly specific TLC fluorescence detection of these drugs [ l l .
In these studies [1,21 treatment of phthalaldehyde, 3,4-dimethoxyphthalaldehyde, and 3-benzoylpyridine-2-carbaldehyde with the 1,5-N-bisnucleophiles yielded products which
have good to moderate fluorescence.
In continuation of these studies we were interested in further
phthalaldehyde analogues such as homophthalaldehyde (l),
whose reactions with amines have scarcely been investigated.
Primary amines, when treated with 1 in the presence of acids,
are known to yield 2-substituted isoquinolinium salts [3,41.
With the aim of finding new reagents for sensitive fluorescence detection of amines, we report the reaction of 1 with
pharmaceutically important 1,3-diamines 2, 8 and o-aminobenzenesulfonamides 13-15.
m
C
H
0
+
CHO
HzN
MeOH
-H20
20°C
,
2
Q
N
CI
Ph
P& \
6
4
H
Results and Discussion
Homophthalaldehyde (1) is commercially not available, but
can be prepared in excellent yields from indan- 1,2-diol by
Malaprade cleavage ['I.
The reaction of homophthalaldehyde (1) with 1,3-diamine
2 in MeOH under N2 at 20 "C led to a non-fluorescent
product, which could be made to fluoresce by stirring in the
presence of air for 12 h. The spectroscopic data of the fluorescent product indicate, that a 1:1 condensation takes place
with elimination of two equivalents of water. In the 'H-NMR
spectrum we observe two characteristically doublets at 6 =
6.34 ppm and 6 = 6.72 ppm, belonging to the adjacent olefinic
protons (5-H and 6-H). A positive NOE between the benzylic
Arch. Pharm. Pharm. Med. Chem.
Scheme 1
5
W
C
I
A further pharmaceutically important 1,3-diamine, 4amino-5-aminomethyl-2-methylpyrimidine (8), was generated by alkaline hydrolysis from the cytostatic Nimustine (7).
The 1,3-diamine 8 was reacted with homophthalaldehyde (1)
to yield the fluorescent pyrimid0[4',5':4,5]pyrimido[2,1a]isoquinoline 9, a first representative of a new heterocyclic
system, and a non-fluorescent compound 11. The structural
elucidation of 9 and 11 was obtained through spectroscopic
means and especially by the use of NO measurements.
0VCH Verlagsgesellschaft mbH, D-69451 Weinheim, 1996
0365-6233/96/0101-0051 $5.00 + .25/0
52
Troschiitz and Heinemann
drochlorothiazide (11) and Bendroflumethiazide (12), led to moderate fluorescent dihydroisoquinobenzothiadiazines 16-18 in good
yields. These however did not oxidize upon stirring in the presence of
air.
The positive NOE of the olefinic
proton (12-H) in 17 on the aromatic
hydrogen atom ( 10-H) indicates the
isoquino[ 1,2-c] [1,2,4]benzothiadiazine system. The structure of 17
was further confirmed by 'H- and
13C-NMR data and C-H-coupling
constants (see experimental). In 17
there exist three characteristic carbon atoms (C-4b, C-12, and C-13)
which are involved in the formation
of the isoquinoline and [ 1,2,4]benzothiazine ring. Their 3C-NMR
signals appear at 6 = 68.4 ppm (d, J
= 156 Hz), 6 = 123.8 ppm (ddd, J I
= 160 Hz, J 2 = 7 Hz, J 3 = 3 Hz), and
6 = 105.6 ppm (dd, J I = 168 Hz, J 2
= 4.4 Hz).
A comparison of the relative fluorescence intensities of the product
f r o m the o-aminobenzenesulfonamide 13 and phthalaldehyde
with 16, has shown that the intensit
of 16 is higher by a factor of 10 L6f
A broad application of homophthalaldehyde (1) as a new fluorescence
reagent for 1,3-diamines and o-aminobenzenesulfonamides seems to
be limited due to its instability. Attempts to synthesize stable derivatives of homophthalaldehyde (1)
are currently being investigated.
Nimustin (7)
c.
I'
n-BuOH
MeOH, 20°C
11
10
Scheme 2
CHO
"~""
H2S04/A,
* I-'s
d '0
'
R2
d "0
H
14 CI
13
15
11
CI
2o'c
2N HCWMeOH
- 2 H20
0
0
CI
S02NH2
CF3S02NH2
S02NH2 H
Scheme 3
The synthesis of 9 from homophthalaldehyde (1) and 8
seems to begin with the formation of an N,N-acetal (as formulated for compound 3 in Scheme 1 ) followed by the
elimination of water and air oxidation. The isoquinolone 11,
another product isolated from the reaction mixture, does not
cyclize to 9 on refluxing in n-butanol. The existence of 11
proves that homophthalaldehyd (1) and diamine 8 can cyclize
in another way, probably via the formation of bir-0,N-acetal
10, which is dehydrated and oxidized to isoquinolone 11.
In the 'H-NMR spectrum of 11 at 6 = 6.3 ppm a typical
broad singlet of a aromatic amino group is observed, which
exchanges upon addition of D2O. The participation of the
aliphatic amino group of diamine 8 in isoquinoline formation
is further evidenced by the observed positive NOE from 3-H
to 6'-H, which is only possible with 11.
The reaction of homophthalaldehyde (1) with o-aminobenzenesulfonamides 13-15, generated by acid hydrolysis from
Diazoxide (10) and 1,2,4-benzothiadiazine diuretics like Hy-
Acknowledgements
The authors are grateful to the following companies for providing us with
drugs: ASTA-MEDICA FrankfurtlMain (Nimustine), Essex Pharma
GmbH Miinchen (Diazoxid), Ciha Geigy GmbH Wehr (Hydrochlorothiazide), IC1 Pharma GmbH Heidelberg (Bendroflumethiazide).
Experimental
General: Mp: Biichi 530 or Linstrom apparatus (uncorr.).- FT-IR: PerkinElmer 1740.- UV: Perkin-Elmer Lambda 5.- 'H-NMR and "C-NMR:
Bruker AM 360; Bruker AC 250; Jeol FX 90 Q (standard: TMS).- EI-MS:
Finnigan MAT TSQ 70.- High Resolution EI-MS: Varian MAT 31 I A or.
Varian MAT 312.- Elementary Analysis: Heracus CHN-Rapid.- MPLC:
Biichi 688.- Silica gel for MPLC: silica gel 60 Macherey Nagel & Co.
IO-Chloro-rY-pherz~/-~f€-isoquino[l,
2-h]yuinazoline ( 5 )
233 mg (1 mmol) 2 was dissolved in 30 ml MeOH and mixed with 148 mg
(1 mmol) of homophthalaldehyde (1). dissolved in 20 ml MeOH. This
Arch. Pharm. Phnmi. Med. Cheuz. 329, 51-53 (1996)
53
Fluorescence Reaction
solution was stirred vigorously at room temperature in the air for 12 h and
evaporated in vacuo. MPLC on silica gel (1. cyclohexaneEtOAc 825:175,
2. CHC13).
Yield 24 mg (7%) pale powder.- mp 183-185 T-IR (KBr): v = 3074
cm-' (Ar), 2924,2887 (CH), 1645,1537, 1487 (C=C, C=N).- UV (MeOH):
A,,,,, (log E) = 223 nm (4.56), 250 (sh, 4.01), 286 (4.13), 296 (4.19), 360 (sh,
3.89),382(4.04),399.3(4.04),421.8(sh,3.79);add.HCI291.7(4.11),303.4
(4.07), 368.4 (3.99), 389 (sh, 3.81).- 'H-NMR (250.14 MHz, CDC13): 6 =
6.10 ppm (s, lH, 8-H), 6.34 (d, J = 7.5 Hz, lH, 5-H), 6.72 (d, J = 7.5 Hz, IH,
6-H) , 6.91 (d, J = 2.5 Hz, 1H, 9-H), 7.18 (dd, J I = 8.5 Hz, J2 = 2.5 Hz, IH,
Il-H),7.23-7.29(m,6H, 12-H,2'-H-6'-H),7.34(dd,J1=7.5Hz, J 2 = 1.5
Hz, IH, 4-H), 7.48 (ddd, J I = J2 = 7.5 Hz, J.? = 1.5 Hz, IH, 3-H), 7.54 (ddd,
J I = J 2 = 7.5 Hz, J3 = 1.5 Hz, lH, 2-H), 8.71 (dd, J I = 7.5 Hz, J2 = 1.5 Ha,
IH, 1-H).- MS (70 eV): m/z (%) = 344/342 (13/39) [M'], 267/265 (33/100)
[M+-C6Hs].- Anal. (CzzHi5CINz) calcd. 342.0923 found 342.0922, fragment (C16HioC1Nz)calcd. 265.0532 found 265.0533 (MS).
I 1 -Methyl-8H-pyrimido[4',5':4,5]pyrimido[2,1 -a]isoquinohne (9)
Preparation according to 5 from 138 mg ( 1 mmol) 8 and 148 mg ( I mmol)
homophthalaldehyde (1). MPLC on silica gel (CHC13MeOH 97:3).
Yield 22 mg (9 %) pale powder.- mp 213-214 "C.- 1R (CHC13):v = 2972
cm-I, 2860 (CH2, CH3), 1645,1519 (C=C, C=N).- UV (MeOH): A,,, (log
E) = 227 nm (4.0), 253 (3.52), 294 (3.59), 302 (3.50), 399 (3.57), 418 (sh,
3.39); add. HCI 238 (3.92), 290 (3.53), 371 (3.26), 412 (3.27).- 'H-NMR
(250.14 MHz, CDC13): 6 = 2.65 pprn (s, 3H, CH3), 5.29 (s, 2H, CHz), 6.73
(d, J = 8.5 Hz, IH, 6-H), 6.85 (d, J = 8.5 Ha, IH, 5-H), 7.48-7.71 (m, 3H,
2-H, 3-H, 4-H), 8.1 1 (s, IH, 9-H), 8.95 (d, J = 8 Hz, IH, I-H).- MS (70 eV):
d z (%) = 248 (65) [M'], 247 (100) [M+-I].- Anal. (C15HlzN4)calcd.
248.1062 found 248.1063 (MS).
2-[4-Amino-2-methylpyrimidine-5-yl)methyl]isoq~inolin-l(2H)-one
(11)
Yield 32 mg (12%) colorless powder.- mp 235-236 Y - IR (KBr): v =
3310,3117 cm-' (NHz), 2982,2921,2852 (CHz, CH3), 1677 (lactam C=O),
1650, 1601 (C=C).- UV (MeOH): Amax (log E) = 277 nm (3.88). 323 (3.37),
335 (3.22); add. HCI 272 (3.87).- 'H-NMR (250.14 MHz, CDCI3): 6 = 2.47
ppm (s, 3H, CH3), 5.05 (s, 2H, CH2), 6.30 (br. s, 2H, NHz, Dz0 exchange),
6.61 (d, J = 7 . 5 Hz, 1H,4-H), 7.10(d, J = 7 . 5 Hz, IH, 3-H), 7.5G7.58 (m,
2H, 5-H, 7-H), 7.68 (ddd, J I = JZ = 7.5 Hz, J3 = 1.5 Hz, lH, 6-H), 8.19 (s,
lH, 6'H), 8.44 (d, J = ca. 7 Hz, IH, 8-H).- I3C-NMR (90,55 MHz, CDC13):
6 = 25.56 ppm (CH3), 45.9 (CHz), 108.3 (C-4), 109.4 (C-S'), 125.7 (C-Xa),
126.2, 127.4 (C-5/-7), 127.6 (C-8), 129.7 (C-3), 132.8 (C-6), 136.8 (C-4a),
156.0 (C-6'), 162.05 (C-4'), 162.17 (C-2'), 163.4 (C=O)- MS (70 eV): d z
(%) = 266 (62) [M'], 122 (loo).-Anal. (CisHi4N40).
J=~~HZ,~H,~~-H),~.O~(~,J=~HZ,~H,I~-H)
10-H), 7.21-7.50 (m, 4H, 1-H, 2-H, 3-H, 4-H), 7.65 (dd, J I = 9 Hz, J2 = 2.5
Hz, lH, 9-H), 7.79 (d, J = 2.5 Hz, lH, 7-H), 9.11 (d, J = 12 Hz,lH, 5-NH,
Dz0 exchange).- MS (70 eV): d z (%) = 320/318 (10/34) [M'], 255/253
(32/100) [M'- SOz-HI.- Anal. (CisHiiClNzOzS).
9-Chloro-8-sulfamoyl-4b,
5-dihydroisoquino[l,
2 -c][l,2,4]benzothiadiazine
6,6-Dioxide(17)
Preparation according to 16 from 142 mg (0.5 mmol) 14 and 74 mg (0.5
mmol) homophthalaldehyde (1).
Yield 181 mg (91 %) pale yellow powder.- mp 305-307 "C
(H20/MeOH).- IR (KBr): v = 3378 cm-', 3258 (SOzNHz, NH), 1642,
1592,1532 (C=C), 1173 (SOzNH).- UV (MeOH): Amax (log E) = 222 nm
(4.62), 243 (sh, 4.31), 270 (3.94), 348 (4.37); add. HC1 267 (4.12), 336
(3.74).- 'H-NMR (250.14 MHz, [D6]DMSO): 6 = 5.98 pprn (d, J = 8 Hz,
IH, 13-H), 6.59 (d, J = 11 Hz, 1H, 4b-H), 7.18-7.45 (m, SH, I-H - 4-H,
12-H), 7.73 (br. s, 3H, 10-H, SOzNHz, DzO exchange s, IH, 10-H), 8.18 (s,
lH, 7-H), 9.28 (d, J = 11 Hz,lH, 5-NH, Dz0 exchange).- 13C-NMR (90.55
MHz, [DhJ-DMSO): 6 (pprn) = 68.4 (d, J I = 156 Hz, C-4b), 105.6 (dd, J I =
168Hz,J~=4.4Hz,C-13),118.7(d,J=169Hz,C-10),123.8(ddd,J~=
160 Hz, JZ = 7 Hz, J3 = 3 Hz, C-12), 124.6 (C-7), 125.52 (C-4), 126 (C-l),
126.2 (C-2), 126.4 (C-I3a), 127.1 (C-8), 129.2 (C-3), 130.4 (C-4a), 132.6
(dd, Ji = 2.4 Hz, J z = 6 Hz, C-64, 135.4 (C-9), 142.2 (C-lOa).- MS (70 eV):
m/z (%) = 399/397 (5115) [M'], 334/332 (34/100) [MfSOz-H].- Anal.
(Ci5HizCIN304Sz).
8-Sulfamoyl-9-trifuoromethyl-4b,5-dihydroisoquino[l,
2-c][I,2,4]benzo-
thiadiazine 6,6-Dioxide(18)
Preparation according to 16 from 160 mg (0.5 mmol) 15 and 74 mg (0.5
mmol) homophthalaldehyde (1).
Yield 196 mg (91 %) yellow powder.-mp 275-278 "C (HzO/MeOH).-IR
(KBr): v = 3429 cm-', 3320,3206 (SOzNHz, NH), 1639,1608,1543 (C=C),
, (log E) = 240 nm (4.0), 346 (4.08); add.
1178 (SOzNH).- UV (MeOH): A
NaOH 246 (4.38), 353 (4.43); add. HCI 238 (4.46), 277 (3.88), 332 (3.54).'H-NMR (250.14 MHz, [D6]DMSO): 6 = 6.0 pprn (d, J = 8 HL, IH, 13-H),
6.63 (br. d, J = 12 Hz, IH, 4b-H), 7.20 (d, J = 8 Hz, IH, 12-H), 7.28-7.40
(m, 4H, 1-H, 2-H, 3-H, 4-H), 7.81 (s, lH, 10-H), 7.84 (br. s, 2H, S02NH2,
Dz0 exchange), 8.44 (s, IH, 7-H), 9.38 (d, J = 12 Hz, lH, 5-H, D20
exchange).- MS (70 eV): m/z ( % ) = 431 (100) [M+].- Anal.
(CI~HI~F~N~O~SZ).
References
R. Troschiitz, 0. Heinemann, R. Waibel, J. Troschiitz, Arch. Pharm.
(Weinheim),1995,328,557-563.
8-Chloro-4b,5-dihydroisoquino[l,2-c][1,2,4]benzothiadiazine
6,6-Dioxide
(16)
R. Troschiitz, 0. Heinemann, Arch. Pharm. Pharm. Med. Chem. 1995,
328,759-764.
103 mg (0.5 mmol) 13 was dissolved in 10 ml 2N HCl and mixed with
74 mg (0.5 mmol) homophthalaldehyde (1) in 30 ml MeOH. After stimng
the solution for 24 h at 20 "C the precipitated product was filtered off, washed
2x with 20 ml Hz0 and 1x with 5 ml MeOHHzO ( 1 :3).The remaining crude
product was crystallized from HzOMeOH.
Yield 151 mg (95 %) pale yellow powder.- mp 203-205 "C
(HzO/MeOH).-IR(KBr): v = 3210cm-' (SOzNH), 1638,1479 (C=C), 1160
(SOzNH).- UV (MeOH): Amax (log E) = 240 nm (4.20), 340 (4.36); add.
NaOH 245 (4.20), 349 (4.38); add. HCI 277 (3.90), 342 (3.73.- 'H-NMR
(250.14 MHz, [D6]DMSO): 6 = 5.86 pprn (d, J = 8 Hz, lH, 13-H), 6.52 (d,
K.T. Potts, R. Robinson, J. Chem. Soc. Perkin Trans. 2, 1955,26752686.
Arch. Phurm. Phurm. Med. Chem. 329,Sl-53 (19%)
T. Sakano, T. Amano, Yakugaku Zasshi 1976,96, 1114-1 121; [Chem.
Abstr. 1976, 85, 182476~1.
B. Wiinsch, M. Zott, Synthesis 1992,927-928.
0. Heinemann, Ph.D. Thesis,Universitat Erlangen-Niimberg, 1994.
Received: July 20, 1995 [FPO44]